SEARCH · PubMed Health

Results for “Generation mean analysis”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

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

At least 343 records · Page 19Linked to original sources

PubMed2001

Analysis of expressed sequence tags (ESTs) from the scaly green flagellate Scherffelia dubia Pascher emend. Melkonian et Preisig.

Partial sequencing of cDNA libraries to generate expressed sequence tags (ESTs) is an effective means of gene discovery, generation of molecular markers and characterization of transcription patterns. We have constructed an EST-database of the scaly green flagellate Scherffelia dubia (Chlorophyta) containing 361 sequences. cDNAs were obtained from interphase cells and from cells regenerating flagella. Analysis of the ESTs identified 138 EST-groups with significant similarity to known sequences. 134 EST-groups showed no significant similarity to any sequences in the databases. Most of the ESTs with similarity to known proteins are associated with typical interphase cell functions of a photosynthetic plant cell: assimilation of nutrients and biosynthesis of proteins. Others are related to the activation of the secretory pathway or the biogenesis of scales (e.g. kdo-synthase). Comparison of S. dubia ESTs with the genome of Arabidopsis thaliana and the EST database of Chlamydomonas reinhardtii revealed that S. dubia ESTs with similarity to known proteins were more similar to sequences in C. reinhardtii than to those of A. thaliana. Additionally, ESTs for guanylyl cyclase and cGMP phosphodiesterase are present in the two flagellates, but so far these gene products have not been found in embryophytes.

3' Untranslated Regions↗

PubMed1996

Two glutamate decarboxylase forms corresponding to the mammalian GAD65 and GAD67 are expressed during development of the chick telencephalon.

The gamma-aminobutyric acid (GABA)-synthesizing enzyme glutamate decarboxylase (GAD) was studied during development of the chick telencephalon. By means of reverse-phase HPLC analysis, we showed that GABA indeed accumulates during embryogenesis, whereas the levels of glutamate, the substrate for GAD, are more or less unchanged up to later developmental stages. The enzyme activity increased approximately 25-fold from embryonic day 3 to embryonic day 17. Immunoblotting data revealed that two GAD proteins, of approximately 65 and 67 kDa, were present during the period investigated. Furthermore, Northern blot analysis with probes obtained from rat cDNA sequences, as well as a chicken-specific probe for GAD65 generated by means of reverse transcriptase-polymerase chain reaction (RT-PCR), strengthened the interpretation that the chick embryo expresses genes corresponding to GAD65 and GAD67. The rat probes recognized transcript sizes of 3.9 kb (GAD65) and 5.6 kb (GAD67), sizes which are different from those of the rat brain (Erlander et al., Neuron, 7, 91-100, 1991). Sequencing of the RT-PCR products revealed a high level of homology (82% at the nucleotide level) between the mammalian and chick GAD65 genes. Taken together, these findings suggest that the chick embryo expresses two GAD genes during embryogenesis. The functional properties of each gene product remain to be investigated.

Amino Acid Sequence↗

PubMed2006

Emotional intelligence in young and middle adulthood: cross-sectional analysis of latent structure and means.

Differentiation of the construct of emotional intelligence was investigated in young and middle-aged adults, on the basis of hypotheses generated from differential emotions theory, discrete emotions functionalist theory, and empirical literature on age-related changes in affective complexity and differentiation of abilities. Both age groups were characterized by the same set of comparably related dimensions. However, midlife adults reported significantly greater use of optimism as a mood-regulation strategy than was reported by young adults. This study considers implications of possible structural continuity in emotional intelligence in conjunction with mean increases in the use of optimism as a strategy for managing affect.

Adult↗

PubMed2004

An analysis of the effect of funding source in randomized clinical trials of second generation antipsychotics for the treatment of schizophrenia.

OBJECTIVE: The effect of funding source on the outcome of randomized controlled trials has been investigated in several medical disciplines; however, psychiatry has been largely excluded from such analyses. In this article, randomized controlled trials of second generation antipsychotics in schizophrenia are reviewed and analyzed with respect to funding source (industry vs. non-industry funding). METHOD: A literature search was conducted for randomized, double-blind trials in which at least one of the tested treatments was a second generation antipsychotic. In each study, design quality and study outcome were assessed quantitatively according to rating scales. Mean quality and outcome scores were compared in the industry-funded studies and non-industry-funded studies. An analysis of the primary author's affiliation with industry was similarly performed. RESULTS: Results of industry-funded studies significantly favored second generation over first generation antipsychotics when compared to non-industry-funded studies. Non-industry-funded studies showed a trend toward higher quality than industry-funded studies; however, the difference between the two was not significant. Also, within the industry-funded studies, outcomes of trials involving first authors employed by industry sponsors demonstrated a trend toward second generation over first generation antipsychotics to a greater degree than did trials involving first authors employed outside the industry (p=0.05). CONCLUSIONS: While the retrospective design of the study limits the strength of the findings, the data suggest that industry bias may occur in randomized controlled trials in schizophrenia. There appears to be several sources by which bias may enter clinical research, including trial design, control of data analysis and multiplicity/redundancy of trials.

Antipsychotic Agents↗

PubMed1997

Nonlinear genetic relationships between traits and their implications on the estimation of genetic parameters.

To estimate nonlinear genetic relationships between traits, formulas based on the paternal halfsib analysis theory were derived. To illustrate the usefulness of the formulas, a series of data sets with halfsib structure for some preselected parameters and sample size situations were generated by means of Monte Carlo techniques. When a nonlinear relationship in the form of a polynomial relationship of degree two is present, the linear and quadratic regression coefficients can be estimated from a paternal halfsib analysis without bias. Some of the traditional linear genetic parameters need correction; however, their value is limited if the relationship between two traits is nonlinear. Although regression coefficients may be estimated appropriately in many situations, the application of the described method is restricted to situations in which the causal flow between the traits involved is clear and the heritability of the determining trait is larger than approximately .10. Further work should be directed to investigation of possibilities for including such parameters in selection decisions in a formalized way.

Analysis of Variance↗

PubMed2001

Transmembrane alpha-helices in the gap junction membrane channel: systematic search of packing models based on the pair potential function.

Recent progress in the field of electron cryo-microscopy and image analysis has shown that there is an overwhelming need to interpret medium resolution (5 to 10 A) three-dimensional maps. Traditional methods of fitting amino acid residues into electron density using molecular modeling programs must be supplemented with further analysis. We have used a potential of mean force (PMF) method, derived from Boltzmann statistics in protein structure, to generate models for the packing of alpha-helices, using pairwise potentials between amino acid residues. The approach was tested using the three-dimensional map of a recombinant cardiac gap junction membrane channel provided by electron cryo-crystallography (Unger et al., 1997; 1999a, 1999b) which had a resolution of 7.5 A in the membrane plane and 21 A in the vertical direction. The dodecameric channel was formed by the end-to-end docking of two hexamers, each of which displayed 24 rods of density in the membrane interior, which was consistent with an alpha-helical conformation for the four transmembrane domains of each connexin subunit. Based on the three-dimensional map and the amino acid sequence for the 4 transmembrane domains determined by hydropathy analysis, we used the modeling utility SymServ (Macke et al., 1998) to build hexameric connexons with 24 transmembrane alpha-helices. Canonical alpha-helices were aligned to the axes of the rods of density and translated along the density so that the center of masses coincided. The PMF function was used to evaluate 162,000 conformations for each of the 24 possible alpha-helical packing models. Since the different packing models yielded different energy distributions, the pair potential function appears to be a promising tool for evaluating the packing of alpha-helices in membrane proteins. The analysis will be refined by energy calculations based on the expectations that the outer boundary of the channel will be formed by hydrophobic residues in contact with the lipids.

Connexins↗

PubMed1996

Magnetoencephalographic analysis of rolandic discharges in benign childhood epilepsy.

We report the detailed analysis of the generator and propagation of rolandic discharges in benign childhood epilepsy with centrotemporal spikes by means of 37-channel magnetoencephalography with neuromagnetic three-dimensional dipole localization. Equivalent current dipoles of prominent negative sharp waves of rolandic discharges appeared as tangential dipoles in the rolandic region, positive poles being situated anteriorly. These equivalent current dipoles showed a relatively limited localization and regular directions compared with other components. Equivalent current dipoles of preceding small positive waves, positive waves following negative sharp waves, and negative slow waves appeared in the vicinity of negative sharp waves. Equivalent current dipoles of rolandic discharges were located around the generator of somatosensory evoked magnetic fields stimulated at the lower lip. These findings suggest that rolandic discharges are generated through basically a mechanism similar to that for the middle-latency components of somatosensory evoked responses.

Child↗

PubMed1991

Mature mRNA 3' end formation stimulates RNA export from the nucleus.

We have analysed nucleocytoplasmic export of mRNAs in primate cells with the aim of identifying signals promoting RNA transport. Our results demonstrate that sequences directing either histone mRNA 3' processing or cleavage/polyadenylation of mRNA stimulate nucleocytoplasmic RNA transport. To elucidate the nature of this stimulation, we engineered test gene transcripts which could obtain a mature histone 3' end by the RNA cleaving activity of a cis-acting ribozyme, thus circumventing the cellular 3' end processing machinery. However, such transcripts were found to be transport deficient and accumulated in the nuclear compartment. Our experiments provide genetic evidence that there is a linkage between 3' end formation and the export of RNA transcripts from the nucleus. Analysis of a similar series of histone mRNAs in which the mature 3' end was generated by means of ribozyme cleavage led to the discovery of a second export mechanism which relies on features specific for mature histone RNA and which can be uncoupled from the cellular processing machinery. The presence of histone mRNA sequences and of the highly conserved histone hairpin structure, positioned close to the 3' terminus, are critical determinants for this export mechanism.

Animals↗

PubMed2005

The use of bootstrap methods for estimating sample size and analysing health-related quality of life outcomes.

Health-related quality of life (HRQoL) measures are increasingly used in trials as primary outcome measures. Investigators are now asking statisticians for advice on how to plan and analyse studies using such outcomes. HRQoL outcomes, like the SF-36, are usual measured on an ordinal scale, although most investigators assume that there exists an underlying continuous latent variable and that the actual measured outcomes (the ordered categories) reflect contiguous intervals along this continuum. The ordinal scaling of HRQoL measures means they tend to generate data that have discrete, bounded and skewed distributions. Thus, standard methods of analysis that assume Normality and constant variance may not be appropriate. For this reason, conventional statistical advice would suggest non-parametric methods be used to analyse HRQoL data. The bootstrap is one such computer intensive non-parametric method for estimating sample sizes and analysing data. We describe three methods of estimating sample sizes for two-group cross-sectional comparisons of HRQoL outcomes. We then compared the power of the three methods for a two-group cross-sectional study design using bootstrap simulation. The results showed that under the location shift alternative hypothesis, conventional methods of sample size estimation performed well, particularly Whitehead's method. Whitehead's method is recommended if the HRQoL outcome has a limited number of discrete values (<7) and/or the expected proportion of cases at either of the bounds is high. If a pilot data set is readily available then bootstrap simulation will provide a more accurate and reliable estimate, than conventional methods.Finally, we used the bootstrap for hypothesis testing and the estimation of standard errors and confidence intervals for parameters, in an example data set. We then compared and contrasted the bootstrap with standard methods of analysing HRQoL outcomes. In the data set studied, with the SF-36 outcome, the use of the bootstrap for estimating sample sizes and analysing HRQoL data produces results similar to conventional statistical methods. These results suggest that bootstrap methods are not more appropriate for analysing HRQoL outcome data than standard methods.

Adolescent↗

PubMed1991

Cell type specification during sea urchin development.

Recent discoveries indicate that cell lineages and fates play a key role in the establishment of spatially restricted gene expression during sea urchin development. Unique sets of founder cells generate five territories of gene expression by means of an invariant pattern of complete cleavage. Cell lineage analysis demonstrates that the second embryonic axis, the oral-aboral axis, is specified with reference to the first cleavage plane. In the undisturbed embryo, clones that contribute to one territory or another begin to appear at the third cleavage, and founder cell segregation to all five territories is completed by the sixth cleavage. Founder cell segregation is a key feature of mechanisms that establish the spatially defined gene activity of sea urchin embryogenesis.

Animals↗

PubMed1982

Maternal age and lifespan do not influence longevity in the rotifer Asplanchna brightwelli.

An analysis of the mean lifespans among the progeny of the viviparous rotifer Asplanchna brightwelli produced during four generations has revealed that longevity of the offspring is not affected by maternal age of the parent or by the parent's lifespan. The production of viable offspring at any time during the parent's reproductive period may be of importance in assuring the continuity of clones of this short-lived rotifer species.

Animals↗

PubMed2005

Cytochrome c oxidase deficient muscle fibres: substantial variation in their proportions within skeletal muscles from patients with mitochondrial myopathy.

Mitochondrial DNA (mtDNA) disease is a common cause of myopathy and the presence of histochemically demonstrated cytochrome c oxidase (COX) deficiency is an extremely useful diagnostic feature. However, there is currently no quantitative information regarding the variability of COX deficiency within or between muscles. This study addresses this issue by studying a number of skeletal muscle samples obtained at post-mortem from three patients with mitochondrial disease due to established mitochondrial DNA defects. COX deficient muscle fibres were enumerated in sections of these muscles and analysed according to patient, individual muscle, position within a particular muscle and sample size. Descriptive statistics were generated followed by an analysis of variance (ANOVA) to assess the effect of these parameters on the mean percentage of COX deficient fibres. We observed statistically significant variation in the percentage of COX deficient fibres within individual muscles from each patient for samples sizes of between 100 and 400 fibres. Our results have implications for the way in which biopsies of skeletal muscle are used for the assessment of disease severity, progression and response to treatment.

Adult↗

PubMed2005

Electronically monitored adherence in outpatients with schizophrenia or schizoaffective disorder: a comparison of first- vs. second-generation antipsychotics.

OBJECTIVE: To examine the effect of first- vs. second-generation antipsychotics on electronically monitored adherence in outpatients with schizophrenia or schizoaffective disorder. METHOD: The sample consisted of 61 outpatients with a DSM-IV diagnosis of schizophrenia or schizoaffective disorder who took either a first-generation (N=25) or second-generation (N=36) oral antipsychotic during study participation. Treatment group designation (first-vs. second-generation antipsychotic) was based on the particular antipsychotic medication the patient was receiving as part of routine care at study entry (i.e., non-random assignment). Adherence to prescribed antipsychotic medication was assessed monthly over a 6-month study period using electronic monitoring (EM) of medication bottle opening. Various participant characteristics were collected at baseline to test for group differences and for potential associations with prospectively measured adherence. The primary data analysis was a mixed-model analysis of repeated measures. RESULTS: The analysis of EM adherence revealed no significant difference between those taking first-generation (6-month adjusted mean adherence=64.35%) and second-generation antipsychotics (6-month adjusted mean adherence=69.17%; Group effect, p=.29) and no significant Group X Period interaction (p=.13). CONCLUSION: There was no statistical difference in EM adherence, over a 6-month period, between patients taking first- and second-generation antipsychotics. However, since the patients were not randomized, conclusions must be interpreted within the context of the quasi-experimental design used in the current study.

Adult↗

PubMed2004

Accuracy of the Nouvag torque control motor for nickel-titanium rotary instruments.

OBJECTIVES: To determine the torque output and examine the accuracy of 5 Nouvag torque control motors. STUDY DESIGN: A handpiece was attached to the motor and gripped with a vise. A size 50 Orifice Shaper, with a 0.07 mm/mm taper was inserted in the handpiece. The instrument tip was clamped in a chuck connected to a torque sensor. Four torque settings were evaluated at 350 rpm. Ten tests were done at each torque setting. A new instrument was used for each test. The means of the torque values generated by the motors at the different torque levels were analyzed using analysis of variance and the Student t test. RESULTS: The actual torque values were significantly higher than the torque preset on the motor (P<.0001) and did not differ significantly among the motors (P>.05). CONCLUSIONS: The actual torque deviated from the preset torque. The usefulness of these motors is questionable.

Analysis of Variance↗

PubMed2000

Conformal proton radiation therapy of the posterior fossa: a study comparing protons with three-dimensional planned photons in limiting dose to auditory structures.

PURPOSE: Conventional radiation therapy for pediatric posterior fossa tumors can cause sequelae such as hearing loss and impairments in language and learning. Modern three-dimensional (3D) treatment techniques have improved dose conformity to the posterior fossa. This report compares the normal tissue dose-sparing capabilities of proton radiation therapy (PRT) with 3D conformal photon plans. METHODS AND MATERIALS: Nine children underwent previous PRT for primary CNS malignancies. Using original planning CT scans, the posterior fossa, inner and middle ear, and temporal lobes were delineated. Three-dimensional treatment plans were generated for protons and photons. Normal tissue exposures were calculated by averaging mean doses received and by analysis of dose-volume histogram. RESULTS: The 95% isodose encompassed the posterior fossa in all plans. Normal structures received markedly less radiation from PRT plans than from 3D photon plans. The cochlea received an average mean of 25 +/- 4% of the prescribed dose from PRT, and 75 +/- 6% from photons. Forty percent of temporal lobe volume was completely excluded using protons; with photons 90% of the temporal lobe received 31% of the dose. CONCLUSION: PRT resulted in increased dose sparing of normal structures analyzed. Posterior fossa conformity of 3D photons came at the expense of increasing amounts of normal tissue receiving low to moderate doses.

Child↗

PubMed1989

A structural model to explain the partial catalytic activity of human prorenin.

Human prorenin, secreted from a Chinese hamster ovary cell line transfected with the cDNA for preprorenin, has been purified in mg quantities by a novel single-step procedure. The method takes advantage of reversible acid activation as a means of generating active prorenin that may be bound and eluted from an affinity column for renin. Analysis of the prorenin so purified revealed that it contained about 80% intact zymogen; the remaining 20% comprised a mixture of various prorenin derivatives truncated in the prosegment, and a small amount of renin. After exposure to 37 degrees C and pH 7.5, the refolded, partially active preparation was passed once more over the affinity column to remove renin and any truncated prorenin forms that were still active and that were, therefore, again retained by the column. Over a period of several hours, refolded and inactive prorenin not bound to the column slowly regains 5% to 10% renin activity, even when maintained under conditions that are optimal for zymogen inactivation. This activity is observed toward both model peptide substrates and natural human angiotensinogen. On the basis of these findings, we propose a model in which, under physiological conditions, a small amount of open, active prorenin is in equilibrium with a predominant, closed, and inactive form of the zymogen. Support for the model is provided by binding studies with a strong renin inhibitor that displaces the equilibrium entirely to a 1:1 zymogen:inhibitor complex. Limited cleavage of prorenin by several different proteinases has provided a number of fully active renin derivatives with varying N-terminal sequences. Results thus obtained, together with analysis of prorenin and its truncated forms bound, or not bound, to the affinity column under a variety of conditions, suggest that the propeptide region, -Arg-Ile-Phe-Leu-Lys- (positions 10P-14P), is essential for the reversible refolding of the prosegment that leads to zymogen inactivation.

Binding Sites↗

PubMed2004

Accuracy of the TCM Endo III torque-control motor for nickel-titanium rotary instruments.

The purpose of this study was to determine the torque output and examine the accuracy of five TCM Endo III torque control motors. A handpiece was attached to the motor and gripped with a vise. A 0.07 taper Orifice Shaper, size 50, was inserted in the handpiece. The instrument tip was clamped in a chuck connected to a torque sensor. Four torque settings were evaluated at 350 rpm. Ten tests were performed at each torque setting. A new instrument was used for each test. The means of the torque values generated by the motors at the different torque levels were analyzed using analysis of variance and post-hoc pairwise comparisons with the Bonferroni test. The actual torque values were significantly higher than the torque preset on the motor (p < 0.0001) and did not differ significantly among the motors (p > 0.05). The actual torque deviated from the preset torque. The usefulness of these motors is questionable.

Analysis of Variance↗

PubMed2005

Assessment in the context of uncertainty: how many members are needed on the panel of reference of a script concordance test?

PURPOSE: The script concordance test (SCT) assesses clinical reasoning in the context of uncertainty. Because there is no single correct answer, scoring is based on a comparison of answers provided by examinees with those provided by members of a panel of reference made up of experienced practitioners. This study aims to determine how many members are needed on the panel to obtain reliable scores to compare against the scores of examinees. METHODS: A group of 80 residents were tested on 73 items (Cronbach's alpha: 0.76). A total of 38 family doctors made up the pool of experienced practitioners, from which 1000 random panels of reference of increasing sizes (5, 10, 15, 20, 25 and 30) were generated with a resampling procedure. Residents' scores were computed for each panel sample. Units of analysis were means of residents' score, test reliability coefficient and correlation coefficient between scores obtained with a given panel of reference versus the scores obtained with the full panel of 38. Statistics were averaged across the 1000 samples for each panel size for the mean and test reliability computations, and across 100 samples for the correlation computation. RESULTS: For sample variability, there was a 3-fold increase in standard deviation of means between a sample panel size of 5 (SD=1.57) and a panel size of 30 (SD=0.50). For reliability, there was a large difference in precision between a panel size of 5 (0.62) and a panel size of 10 (0.70). When the panel size was over 20, the gain became negligible (0.74 for 20 and 0.76 for 38). For correlation, the mean correlation coefficient values were 0.90 with 5 panel members, 0.95 with 10 members and 0.98 with 20 members. CONCLUSION: Any number over 10 is associated with acceptable reliability and good correlation between the samples versus the full panel of 38. For high stake examinations, using a panel of 20 members is recommended. Recruiting more than 20 panel members shows only a marginal benefit in terms of psychometric properties.

Adult↗