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 1,063 records · Page 59Linked to original sources
PubMed1986

Long-term effects of spinal cord transection on fast and slow rat skeletal muscle. I. Contractile properties.

Contractile properties of rat soleus and extensor digitorum longus muscles were studied 1 year after complete thoracic spinal cord transection (spinal cord level T9). Force-generating capacity and contraction speed were unchanged in the extensor digitorum longus 1 year after transection. However, the rate of contraction and relaxation increased in the soleus as reflected by a decrease in time-to-peak tension and increase in fusion frequency. Additionally, the soleus muscle cross-sectional area decreased significantly (50%) while generating the same absolute tension. Thus, a large increase in soleus specific tension (force per unit area) was observed. These data, in conjunction with the increase in contractile speeds, suggest soleus slow-to-fast fiber type conversion secondary to cordotomy. Discriminant analysis of the contractile properties yields fusion frequency as the best discriminator between muscle groups. Thus, following cordotomy, predominantly slow muscles are affected to a greater extent than fast muscles.

Analysis of Variance↗
PubMed1987

Quantum noise in X-ray image intensifiers.

Explicit expressions are given for the relative variance of the output screen of X-ray image intensifiers, and for detection quantum efficiency as a function of the technical features of the intensifier. The analysis takes into account all conversion stages and physical processes inside the image intensifier and includes a special treatment of scintillation. The results are analysed numerically both for previously reported approximations and for applying this more recent method of detailed visibility calculations.

Biomedical Engineering↗
PubMed1989

Cloning and expression of a collagen-analog-encoding synthetic gene in Escherichia coli.

A family of totally synthetic genes coding for multiple tandem repeats of the amino acid sequence (Gly-Pro-Pro) has been prepared and inserted into the ClaI cloning site of the expression vector pJL6. A representative recombinant plasmid, pAC1, with an insert of about 340 bp was established in an Escherichia coli strain bearing a defective lambda prophage, to study expression of the CII-collagen analog fusion protein produced from pAC1 upon heat induction. Authentic fusion protein production was demonstrated by nucleotide sequencing, Northern-blot analysis, and in vivo synthesis. Conversion of a wild-type rpoH allele to the rpoH165 mutation was shown to suppress proteolysis of the unstable fusion protein.

Amino Acid Sequence↗
PubMedDate not supplied

3D base: a geometrical data base system for the analysis and visualisation of 3D-shapes obtained from parallel serial sections including three different geometrical representations.

In this paper we discuss a geometrical data base that includes three different geometrical representations of one and the same reconstructed 3D shape: the contour-pile, the voxel enumeration, and the triangulation of a surface. The data base is tailored for 3D shapes obtained from plan-parallel serial sections. It is explained how this geometrical data base is useful with the different processing approaches of a 3D shape, such as analysis and visualisation. Methods of conversion between the geometrical representations are discussed. Examples of the operation of the data base as it is embedded in a data base management system are given by illustrations of retrieval of geometrical information.

Algorithms↗
PubMed2005

Long-lasting synapse formation in cultured rat hippocampal neurons after repeated PKA activation.

Recently, we reported that the repeated activation of cyclic-AMP-dependent protein kinase (PKA) in the rat hippocampus under tissue culture conditions induced the enhancement of excitatory postsynaptic potential (EPSP), which lasted more than 2 weeks and was accompanied by the formation of morphologically identifiable synapses. Here we examined whether an equivalent synapse formation is induced in dissociated cell cultures of rat hippocampal neurons. Brief (15-min) application of Sp-cAMPS (a membrane-permeable analog of cyclic AMP) induced an increase in the number of synaptic sites (identified by the apposition of immunocytochemically labeled pre- and postsynaptic structures). There were two types of increase: a short-lasting one that lasted less than 24 h after a single application of Sp-cAMPS, and a long-lasting one that lasted more than 2 weeks after repeated applications. The long-lasting increase in synaptic sites was dependent on the time and interval of application and was suppressed by Rp-cAMPS (a PKA inhibitor). The synapses were judged to be active based on the endocytosis of FM1-43, a fluorescent dye. Electron microscopy confirmed the increase in the number of synaptic ultrastructures. The present results show that the synaptogenesis induced by repeated PKA activation is reproducible in a neuronal network that is reconstituted under dissociated cell culture conditions. This experimental system, together with the synaptogenesis in the slice culture system described previously, serves as a good in vitro model for the analysis of the process of conversion from short-lasting plasticity (lasting for hours) into a long-lasting one (lasting for days-weeks).

Animals↗
PubMed2006

A simple modification of Ciaglia Blue Rhino technique for tracheostomy: using a guidewire dilating forceps for initial dilation.

OBJECTIVE: The potential difficulty in doing initial dilation in the percutaneous dilational tracheostomy (PDT) with the Ciaglia Blue Rhino (CBR) technique has been reported by others and encountered in our clinical practice. To resolve this problem, we developed a modified CBR technique by using a guidewire dilating forceps (GWDF) to facilitate initial dilation. The present before-and-after comparison study aimed to evaluate the clinical benefits of this modified CBR technique. METHODS: Consecutive 120 patients undergoing CBR technique in the pre-conversion year and 114 patients undergoing GWDF-CBR technique in the post-conversion year were enrolled for analysis. The procedure time and procedure-related complications were compared between these two groups. RESULTS: The mean procedure time with GWDF-CBR technique was 4.5+/-1.6min, significantly shorter than 5.7+/-3.0min with CBR technique (p<0.001). Only two patients in the GWDF-CBR group required prolonged procedure time (>8min), compared with 14 patients in the CBR group. Thirty three (27.5%) of 120 patients undergoing CBR technique and 15 (13.1%) of 114 patients undergoing GWDF-CBR technique had PDT-related complications (p=0.006). Most of the complications were minor and transient. Only 13 patients in the CBR group and 3 patients in the GWDF-CBR group encountered major complications (10.8% vs 2.6%, p=0.012). Regarding the high-risk patients, 21 (36.2%) of 58 patients in the CBR group and 9 (15.8%) of 57 patients in the GWDF-CBR group had PDT-related complications (p=0.011). CONCLUSIONS: Pre-dilation with a GWDF in the CBR technique helped to prevent prolonged procedure time and procedure-related complications. We suggest that the bronchoscopy-guided GWDF-CBR serves an easy-to-operate and relatively safe PDT technique for critically ill patients.

Adolescent↗
PubMed2005

Adjuvant procedures performed during endovascular repair of abdominal aortic aneurysm. does it influence outcome?

OBJECTIVE: The purpose of this study was to assess whether there is a difference in outcome of endovascular repair in patients with and without intraoperative adjuvant procedures. METHODS: Demographic, anatomic and operative details were assessed in patients undergoing endovascular repair using the EUROSTAR registry and correlated with morbidity and mortality rates. Three groups of adjuvant procedures: (A) endovascular, (B) surgical peripheral arterial and (C) surgical abdominal arterial were compared with a group of patients without an adjuvant procedure (D). Logistic regression and Cox proportional hazards model were used for statistical analysis. RESULTS: Of 4631 endovascular repairs, 1353 patients (29.2%) required adjuvant procedures. Additional endovascular procedures were performed in 1057 (78.1%), surgical peripheral arterial in 193 (14.3%) and surgical abdominal arterial in 103 (7.6%). The 30-day mortality rate was significantly higher in categories with peripheral arterial surgical (6.7%) and abdominal surgical procedures (7.8%) compared to patients without adjuvant procedures (1.5%, p = .001 and p = .004, respectively). Life-table-analysis demonstrated that late mortality, conversion or rupture rates were not increased in patients with an adjuvant procedure. CONCLUSION: Adjuvant surgical procedures were associated with increased 30-day mortality. Because of this higher risk, endovascular repair should be recommended with caution when surgical adjuvant procedures are anticipated.

Aged↗
PubMed2005

Development of a S. cerevisiae whole cell biocatalyst for in vitro sialylation of oligosaccharides.

Absence of sialylation on recombinant glycoproteins compromises their efficacy as therapeutic agents, as it results in rapid clearance from the human bloodstream. To circumvent this, several strategies are followed, including the implementation of a post-secretion glycosylation step. In this paper we describe the engineering of yeast cells expressing active surface exposed Trypanosoma cruzi trans-sialidase (TS) fused to the yeast Aga2 protein, and the use of this yeast in the sialylation of synthetic oligosaccharides. In an attempt to improve overall protein accessibility on the yeast surface, we abolished hyperglycosylation on the yeast cell wall proteins. This was achieved by disrupting the OCH1 gene of the TS surface expressing strain, which resulted in increased enzymatic activity. Using a fluorescence-based activity assay and DSA-FACE structural analysis, we obtained almost complete conversion to a fully sialylated acceptor, whereas in the wild type situation this conversion was only partial. Increasing protein accessibility on the yeast surface by modifying the glycosylation content thus proved to be a valuable approach in increasing the cell wall associated activity of an immobilised enzyme, hence resulting in a more effective biocatalyst system.

Catalysis↗
PubMed2005

Dihydroorotase from Escherichia coli: loop movement and cooperativity between subunits.

Escherichia coli dihydroorotase has been crystallized in the presence of the product, L-dihydroorotate (L-DHO), and the structure refined at 1.9A resolution. The structure confirms that previously reported (PDB entry 1J79), crystallized in the presence of the substrate N-carbamyl-D,L-aspartate (D, L-CA-asp), which had a dimer in the asymmetric unit, with one subunit having the substrate, L-CA-asp bound at the active site and the other having L-DHO. Importantly, no explanation for the unusual structure was given. Our results now show that a loop comprised of residues 105-115 has different conformations in the two subunits. In the case of the L-CA-asp-bound subunit, this loop reaches in toward the active site and makes hydrogen-bonding contact with the bound substrate molecule. For the L-DHO-bound subunit, the loop faces in the opposite direction and forms part of the surface of the protein. Analysis of the kinetics for conversion of L-DHO to L-CA-asp at low concentrations of L-DHO shows positive cooperativity with a Hill coefficient n=1.57(+/-0.13). Communication between subunits in the dimer may occur via cooperative conformational changes of the side-chains of a tripeptide from each subunit: Arg256-His257-Arg258, near the subunit interface.

Amino Acid Sequence↗
PubMed2006

Clinic consultations with children and parents on the dietary management of cystic fibrosis.

This paper examines clinic consultations on the dietary management of cystic fibrosis (CF) with particular consideration to the role of children. The role of parents is also examined to determine how their involvement impacts on the role of children during consultations. The data are drawn from interviews with 32 Irish school aged children with cystic fibrosis and their parents, and participant observations during clinic consultations with a sub-group of 21 children. Data were analysed concurrently with data collection using a method of constant comparison, which involved comparing and contrasting incidents in the data to develop themes. Theoretical sampling was used to further explore and develop emergent themes. Discourse analysis was applied to clinic conversations. Children were seen to have little active involvement during consultations, leaving them marginalised, as conversations were directed at parents primarily, whose accounts were privileged over those of children. A surveillance approach to consultations involving interrogative style questioning and generally closed conversations was seen to contribute to the marginalised position of children. In addition, dietary advice limited children's involvement because it was of little relevance to their understandings of being healthy and the dietary implications of these. The findings highlight a need to acknowledge children as active participants in their dietary care. Implications for developing a child-centred approach to dietary consultations are discussed, including implications for working with children towards improved health outcomes of managing CF diet.

Ambulatory Care Facilities↗
PubMed2006

On the statistics of ultrasonic spectral parameters.

Several factors affect the accuracy and precision of ultrasonic spectrum analysis, which is used for characterization of normal and diseased tissue in a variety of organs. For example, averaging procedures and the sequence of operations affect the accuracy and precision of spectrum analysis. Averaging procedures and logarithmic conversion (i.e., conversion to dB) introduce a constant bias that affects spectral amplitudes and the values of intercept and midband fit; the bias depends on the sequencing of the log conversion and averaging as well as the number of independent spectra or spectral parameters that are averaged. We derive expressions that permit correction of such biases. Furthermore, we show that standard deviations for slope and midband-fit estimation can be minimized by averaging spectra before dB conversion and before computing spectral parameters by linear regression. Experimental results using phantoms agree remarkably with theoretical predictions for the data window functions studied in this article, Hamming and rectangular.

Humans↗
PubMed1986

Characterization of structural unit of phospholamban by amino acid sequencing and electrophoretic analysis.

The partial amino acid sequence of phospholamban from canine cardiac sarcoplasmic reticulum was determined by sequence analysis of the peptides obtained from the protein cleaved by cyanogen bromide and with TPCK-trypsin. The sequence determined initiated with N alpha-acetylated methionine followed by 44 amino acid residues intervening two unidentified residues. This polypeptide would represent a structural unit (protomer) of phospholamban. Analysis of temperature-dependent conversion of phospholamban from 26 kDa to lower molecular weight form (6 kDa) suggested that phospholamban holoprotein is composed of five identical protomers.

Amino Acid Sequence↗
PubMed1999

A comparison of amino acid distance measures using procrustes analysis.

Four methods to convert an amino acid similarity matrix into a metric distance matrix were compared using procrustes analysis. Procrustes analysis is a rotational fit technique, which assesses the degree of fit between two configurations after optimal matching of the two matrices under translation, rotation and scaling. The analysis shows that not all conversion methods are equivalent, but that the results of two methods are more similar than the others.

Amino Acids↗
PubMed1984

Energy transformation and entropy production in living systems I. Applications to embryonic growth.

Generalized material and energy balances are presented for biological systems that experience negligible kinetic, elastic, and potential energy changes. The balances are used to characterize the mass changes and energy transformations that occur in the developing avian embryo, using as an example a consistent set of data for the chicken egg. It is shown that the rate of total chemical energy turnover by the embryo is a quantity of interest and that this rate is not necessarily equivalent to the metabolic rate that is predicted from heat transfer measurements or oxygen consumption rates. The energy required for evaporative water loss is accounted for in the overall energy balance. Using the results of the energy calculations and a generalized expression for the rates of internal and total entropy production, the Prigogine-Wiame hypothesis is examined for the developing embryo with two different assumptions regarding the efficiency of biomass conversion. An order of magnitude analysis of the internal heat-conduction term is performed to show that the chemical reaction term dominates the entropy production relation. The constant efficiency case is shown to be in agreement with the Prigogine-Wiame hypothesis for the data used in the analysis.

Animals↗
PubMed2002

Fungal melanin inhibitor and related compounds from Penicillium decumbens.

Two polyketides, decumbenones A and B, and versiol were isolated from the culture filtrate of the fungus, Penicillium decumbens. Their respective structures were 1-(2,8-dihydroxy-1,2,6-trimethyl-1,2,6,7,8,8a-hexahydronaphthalen-1-yl)-3-hydroxy-1-propanone and 1-(2,8-dihydroxy-1,2,6-trimethyl-1,2,4a,5,6,7,8,8a-octahydronaphthalen-1-yl)-3-hydroxy-1-propanone based on NMR spectroscopic data, chemical conversion, and X-ray analysis. Decumbenone A inhibited melanization in Magnaporthe grisea, the rice blast pathogen, whereas decumbenone B like versiol did not.

Crystallography, X-Ray↗
PubMed1997

Measurement of dexfenfluramine metabolism in rat liver microsomes by gas chromatography-mass spectrometry.

A specific and useful method was developed for the determination of dexfenfluramine metabolism by microsomal systems utilising GC-MS. The synthesis of two metabolites 1-(3-trifluoromethylphenyl)propan-2-ol ('alcohol') and 1-(3-trifluoromethylphenyl)-1,2-propanediol ('diol') via straightforward routes, were confirmed by MS and NMR spectra. The conditions for extraction from alkalinised microsomal mixtures of the metabolites nordexfenfluramine, 1-(3-trifluoromethylphenyl)propan-2-one ('ketone'), alcohol and diol, their conversion to trifluoroacetate derivatives and analysis by GC-MS-SIM are described. Calibration curves were constructed between 48 and 9662 nM and fitted to quadratic equations (r2>0.999). The method precision was good over low (121 nM) medium (2415 nM) and above medium (9662 nM) concentrations for all metabolites; the within- and day-to-day coefficients of variation ranged between 2.5-12.4% and 6.7-17.5%, respectively. The accuracy, measured as bias, was very good both within- and day-to-day (range: -0.4-12.6%, 0.8-18.9%). For most metabolites, the C.V. for the assay and bias increased at 121 nM. Dexfenfluramine metabolism by rat liver microsomes was investigated using the assay method and showed a concentration dependent increase in nordexfenfluramine and ketone metabolites over the substrate range of 5-200 microM.

Animals↗
PubMed2000

Coumarinic derivatives as mechanism-based inhibitors of alpha-chymotrypsin and human leukocyte elastase.

Novel coumarinic derivatives were synthesized and tested for their inhibitory potency toward alpha-CT and HLE. Cycloalkyl esters and amides were found to be essentially inactive on both enzymes. On the opposite, aromatic esters strongly inactivated alpha-CT whereas HLE was less efficiently inhibited with dichlorophenyl ester derivatives (kinact/K(I) = 4000 M(-1) s(-1) for 36). Representative examples of amide, ester, thioester and ketone derivatives were prepared in order to evaluate the influence of the link between the coumarinic ring and the phenyl side chain. The irreversible inactivation of alpha-CT by 6-chloromethyl derivatives should be due to alkylation of a histidine residue as suggested by the amino acid analysis of the modified chymotrypsin. Conversely the inhibition of HLE was transient. Intrinsic reactivity of coumarins has been calculated using a model of a nucleophilic reaction between the ligand and the couple methanol-water. From this calculation, it appears that differences in the inhibitory potency expressed by these molecules cannot only be explained by differences in the reactivity of the lactonic carbonyl group toward the nucleophilic attack.

Chymotrypsin↗
PubMed2004

Receptor binding kinetics and cellular responses of six N-formyl peptide agonists in human neutrophils.

The goal of this study was to elucidate the relationships between early ligand binding/receptor processing events and cellular responses for the N-formyl peptide receptor system on human neutrophils as a model of a GPCR system in a physiologically relevant context. Binding kinetics of N-formyl-methionyl-leucyl-phenylalanyl-phenylalanyl-lysine-fluorescein and N-formyl-valyl-leucyl-phenylalanyl-lysine-fluorescein to the N-formyl peptide receptor on human neutrophils were characterized and combined with previously published binding data for four other ligands. Binding was best fit by an interconverting two-receptor state model that included a low affinity receptor state that converted to a high affinity state. Response behaviors elicited at 37 degrees C by the six different agonists for the N-formyl peptide receptor were measured. Dose response curves for oxidant production, actin polymerization, and G-protein activation were obtained for each ligand; whereas all ligands showed equal efficacy for all three responses, the ED(50) values varied as much as 7000-fold. The level of agonism and rank order of potencies of ligands for actin and oxidant responses were the same as for the G-protein activation assay, suggesting that the differences in abilities of ligands to mediate responses were determined upstream of G-protein activation at the level of ligand-receptor interactions. The rate constants governing ligand binding and receptor affinity conversion were ligand-dependent. Analysis of the forward and reverse rate constants governing binding to the proposed signaling receptor state showed that it was of a similar energy for all six ligands, suggesting the hypothesis that ligand efficacy is dictated by the energy state of this ligand-receptor complex. However, the interconverting two-receptor state model was not sufficient to predict response potency, suggesting the presence of receptor states not discriminated by the binding data.

Actins↗