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At least 793 records · Page 44Linked to original sources

PubMed2003

Clinical comparison of two self-directed bleaching systems.

PURPOSE: This randomized clinical trial compared the clinical efficacy and tolerability of 2 marketed self-directed vital tooth-whitening systems. MATERIALS AND METHODS: Balancing for baseline tooth color, self-reported coffee/tea use, and age, 57 adult volunteers were randomized to either a whitening strip containing 6% hydrogen peroxide or a tray-based 10% carbamide peroxide/dentifrice/mouth rinse combination system. Following the manufacturer's directions, the strip group bleached twice daily for 30 minutes, whereas the tray group bleached twice daily for 20-30 minutes, preceded by tooth brushing with a whitening dentifrice and followed by mouth rinsing with a whitening solution. Treatment extended for 14 days, with evaluation at day 7 and again at day 14. Whitening response was measured objectively as L*a*b* from standardized digital images of maxillary anterior teeth. Tolerability was assessed by oral examination and subject interview. Efficacy comparisons were made using analysis of covariance, whereas tolerability was compared using the nonparametric Wilcoxon rank-sum test. RESULTS: Both treatments resulted in statistically significant (P < 0.01) improvements from baseline for all color parameters. For between-group comparisons, the 6% hydrogen peroxide strips yielded a nearly 3-fold reduction in yellowness (deltab*), a nearly 2-fold improvement in lightness (deltaL*), 2.6 times greater redness reduction (deltaa*), and a more than 2-fold change in overall color (deltaE*) compared to the tray-based combination system. Between-group comparisons were statistically significant for the all color parameters at both the day 7 and day 14 evaluations (P < 0.001). In general, 7-day use of the whitening strips provided significantly greater color improvement relative to the combination dentifrice/gel/rinse system at day 14. In addition, the groups differed significantly (P < 0.05) in bleaching tolerability severity-days, with the strip system demonstrating better overall tolerability compared to the combination system. CONCLUSIONS: The single-step 6% hydrogen peroxide strips demonstrated better overall clinical response, in terms of both tooth-whitening efficacy and tolerability, than the multiple-step tray-based combination system.

Adolescent↗

PubMedDate not supplied

Repair of the achilles tendon rupture: a functional comparison of three surgical techniques.

A retrospective comparison of three surgical procedures for the acute treatment of closed ruptures of the Achilles tendon is presented: 1) open repair, 2) a percutaneous technique, and 3) a combined mini-open and percutaneous technique. The authors compared the results of 52 tendon ruptures, including 15 open repairs, 15 percutaneous repairs, and 22 combined repairs, with minimal follow-up of 12 months. The authors evaluated the parameters of strength, performance, use of shoes, time of returning to work, range of ankle motion, calf circumference, pain, ability to perform 20 toe-raises on each side, and MRI findings. In comparison to the uninjured leg, the strength of the involved extremity was 74% in the patients with an open repair, 88% in patients with a percutaneous repair, and 92% in the combined mini-open and percutaneous procedure. The combined mini-open and percutaneous repair gave significantly better results than the other surgical procedures. On MRI, the area of the posterior calf of the injured leg, in comparison to the contralateral uninjured leg was 82% in open repair, 81% in the percutaneous procedure, and 91% in combined mini-open and percutaneous procedure. These differences were found to be statistically significant (p < .01). On the basis of their results, the authors prefer to perform the combined percutaneous and mini-open repair of Kakiuchi for the repair of acute Achilles tendon ruptures.

Achilles Tendon↗

PubMedDate not supplied

Forensic hair morphology comparison--a dying art or junk science?

There has been debate in both the judicial and forensic fields concerning the admissibility and reliability of the so-called forensic comparison sciences such as handwriting, tool mark analyses, and hair analysis. In particular, there has been increasing controversy over the use and interpretation of hair comparison evidence and it has been held partly responsible for miscarriages of justice. There has also been a perceived devaluation of the worth of microscopic human hair analysis particularly since the advent of DNA profiling. This article will attempt to initiate discussion on the past, current and future role of forensic human hair analysis and comparison.

Attitude↗

PubMed2003

Comparison of different HCV viral load and genotyping assays.

BACKGROUND: We report an interlaboratory comparison of methods for the determination of hepatitis C virus (HCV) serum load and genotype between a recently, established molecular laboratory at the Alaska Native Medical Center (ANMC) and two independent laboratories using different assays. At ANMC, a Real-time quantitative RT-PCR amplification methodology (QPCR) has been developed in which HCV viral loads are determined by interpolation of QPCR results to those of standards calibrated to the World Health Organization (WHO) First International Standard for HCV. HCV genotype is subsequently determined by direct sequencing of the DNA fragment generated from the QPCR assay. OBJECTIVES AND STUDY DESIGN: The above methods were statistically compared to results obtained for the same patient sera by two independent laboratories using different commercially available viral load assays; Quantiplex HCV RNA (Bayer Diagnostics) and Amplicor HCV Monitor (v 2.0) (Roche Molecular Systems), as well as two different genotyping assays; restriction fragment length polymorphism (RFLP) and INNO-LiPA HCV II (Innogenetics). RESULTS: ANMC's Real-time QPCR HCV viral load results compared moderately well with those obtained by the Quantiplex HCV RNA method (R2=0.3813), and compared quite well with recent lot numbers of Amplicor HCV Monitor in which viral loads are derived in IU/ml (R2=0.6408), but compared poorly with earlier lot numbers of Amplicor HCV Monitor in which viral loads were derived in copies/ml (R2=0.0913). The ANMC direct sequencing method for genotype determination compared moderately to very well with both the RFLP (84-86%) and INNO-LiPA (85-97.5%) methods. CONCLUSIONS: These viral load comparisons highlight the discrepancies that may occur when patient HCV viral loads are monitored using different types of assays. Comparison of HCV genotype by different methods is more reliable statistically and important clinically for predicting probability of response to antiviral therapy. However, viral loads are important for monitoring response once therapy has begun.

Evaluation Studies as Topic↗

PubMed2001

Comparison of actigraphic, polysomnographic, and subjective assessment of sleep parameters in sleep-disordered patients.

OBJECTIVE: Comparison of polysomnography (PSG)-derived sleep parameters (total sleep time, sleep efficiency, and number of awakenings) to those derived from actigraphy and subjective questionnaires. BACKGROUND: Actigraphy is commonly used to assist sleep specialists in the diagnosis of various sleep and circadian-rhythm disorders. However, few validation studies incorporate large sample sizes, typical sleep clinic patients, or comparisons with subjective reports of sleep parameters. METHODS: Clinical series with 100 consecutive sleep-disordered patients (69 men, 31 women, mean age of 49+/-14.7 years) at a tertiary sleep disorders center. Sensitivity, specificity, and accuracy measures were obtained from epoch-by-epoch comparison of PSG and actigraphic data. Subjective sleep parameter data were derived from questionnaires given to subjects in the morning following their recording night. RESULTS: We found that total sleep time and sleep efficiency did not significantly differ between PSG data and the combined data obtained from actigraphy and subjective reports. Using a high-threshold (low-wake-sensitivity) actigraphic algorithm, the number of awakenings was not significantly different from those detected by PSG. CONCLUSIONS: We recommend the use of subjective data as an adjunct to actigraphic data in estimating total sleep time and sleep efficiency in sleep-disordered patients, especially those with disorders of excessive somnolence.

Journal Article↗

PubMed2006

Firm embryo transfer catheters for assisted reproduction: a systematic review and meta-analysis using direct and adjusted indirect comparisons.

A systematic review of published evidence on firm embryo transfer catheters is presented. Extensive searches were conducted for full-text manuscripts, abstracts, ongoing and unpublished trials. Direct and adjusted indirect comparisons were undertaken, where appropriate. Twenty-six randomized controlled trials comparing embryo transfer catheters were identified. Only two trials (314 transfers) compared different firm embryo catheters. Using direct comparison, both the Tom Cat and Tefcat catheters demonstrated statistically significant increased chances of clinical pregnancy compared with the Tight Difficult Transfer (TDT) catheter (P=0.007; OR=3.67, 95% CI=1.48-9.10 and P<0.0001; OR=4.71, 95% CI=2.34-9.48 respectively). The implantation rates were also higher with the Tom Cat and Tefcat catheters than the TDT catheter (P=0.005; OR=3.67, 95% CI=1.48-9.10 and P<0.00001; OR=4.29, 95% CI=2.45-7.50 respectively). Using adjusted indirect comparison, Tom Cat and Tefcat catheters were compared, and shown to have similar pregnancy and implantation rates (OR=0.99; 95% CI=-0.87-1.79 and OR=0.86; 95% CI=-0.77-1.35). In conclusion, both Tom Cat and Tefcat catheters give better outcomes than the TDT catheter, but are similar to each other.

Catheterization↗

PubMedDate not supplied

Qualitative comparison of dietary choices and dietary supplement use among older adults with and without a history of colorectal cancer.

OBJECTIVE: To explore colorectal cancer survivors' beliefs about diet, dietary supplements, health, and cancer in relation to beliefs of a similar group without colorectal cancer. DESIGN: In-depth, semistructured, open-ended interviews were used to examine perceptions. PARTICIPANTS: Twenty-two participants (10 colorectal cancer survivors and 12 from a comparison group) from the North Carolina Strategies for Improving Diet, Exercise, and Screening Study. ANALYSIS: Verbatim interview transcripts were coded and analyzed. Comparisons were made between colorectal cancer survivors and the comparison group. RESULTS: Three main themes emerged: the influence of significant life events on dietary change, concerns about contaminants in the food supply, and a lack of physician guidance in dietary supplement selection. CONCLUSION AND IMPLICATIONS: The experience of colorectal cancer is significant and may lead to dietary change among some survivors, but these findings do not suggest that it is necessarily more influential than other life events. Participants sought to control diet (for coping or survival) and also felt that diet cannot be controlled (due to the contamination of the food supply). Although many lacked guidance from physicians about dietary supplements, they were comfortable making their own decisions to self-treat. Enhanced understanding of the themes that guide selection of diet and dietary supplements can provide a context for dietitians in practice and researchers conducting behavioral interventions.

Aged↗

PubMedDate not supplied

Evaluation of positron emission tomography imaging using [68Ga]-DOTA-D Phe(1)-Tyr(3)-Octreotide in comparison to [111In]-DTPAOC SPECT. First results in patients with neuroendocrine tumors.

PURPOSE: [111In]-DTPAOC (Octreoscan(R)) has been shown to be very useful in the detection of somatostatin receptor (SSTR) positive tumors and their metastases using either conventional scintigraphy or single photon emission computed tomography (SPECT). The main drawback of this method is the limited spatial resolution and a somewhat low receptor affinity of the radiopeptide. Due to the increased spatial resolution and the ability of quantification, an agent for positron emission tomography (PET) imaging of SSTR is desirable. This communication shows our initial experience using [68Ga]-DOTA-D-Phe(1)-Tyr(3)-Octreotide (DOTATOC) in comparison to [111In]-DTPAOC-SPECT in patients with neuroendocrine tumors. PROCEDURES: Four patients, two male and two female (46-55 years old) have been examined by [111In]-DTPAOC scintigraphy and within one month by [68Ga]-DOTATOC-PET. All of them suffered from neuroendocrine tumors and/or their metastases. DOTATOC has been labeled using the positron-emitting generator-nuclide 68Ga (t(1/2) 68 minutes). In two patients with previously known localization of tumor, dynamic PET scans after intravenous bolus-injection of 181+/-17 MBq [68Ga]-DOTATOC until 120 minutes post-injection were acquired. In all patients, the static PET-scans have been acquired after 45 or 60 minutes post-injection (SUV1) and 140 minutes post-injection (SUV2). RESULTS: Similar to [111In]-DTPAOC, [68Ga]-DOTATOC showed the highest uptake in the spleen, followed by the kidneys and the liver. A clear delineation of the pituitary gland could only be achieved by PET. The highest SUVs were found at a plateau between 45 and 90 minutes with a maximum 60 minutes post-injection. Due to the fast tracer accumulation in the tumor and the rapid clearance of the compound, resulting in high tumor to background ratios even 40 minutes after injection, the short half life of 68Ga is reasonable. In two patients more findings have been revealed by [68Ga]-DOTATOC-PET as compared to the [111In]-DTPAOC-SPECT. In comparison to the [111In]-DTPAOC-SPECT [68Ga]-DOTATOC-PET seems to be superior especially concerning small findings with low tracer uptake. Both [111In]-DTPAOC-SPECT and [68Ga]-DOTATOC-PET were less sensitive in the detection of liver metastases of neuroendocrine tumors compared to computerized tomography CT because they showed a lower uptake than the surrounding liver tissue. CONCLUSIONS: According to our initial experiences in a limited number of patients, [68Ga]-DOTATOC is a promising PET tracer for imaging neuroendocrine tumors and their metastases. In comparison to the [111In]-DTPAOC-scan it seems to be superior especially in detecting small tumors or tumors bearing only a low density of SSTRs. It offers excellent imaging properties and very high tumor to background ratios. Further evaluation of [68Ga]-DOTATOC in a larger number of patients is certainly justified.

Carcinoid Tumor↗

PubMed1999

Attempted suicide in west London, II. Inter-group comparisons.

BACKGROUND: Previous studies of attempted suicide have suggested that cultural and social factors play a significant role in the causation of deliberate self-harm. METHOD: In order to measure elements of culture conflict two inter-group comparisons were undertaken. In the first, 27 Asian women who had presented to hospital services following attempted suicide (Asian group) were matched with a group of similar age Asian women attending GP surgeries for other reasons (Asian GP attenders group). The second comparison was between the Asian and 46 White attempters. RESULTS: On comparing Asian attempters with Asian GP attenders group the former were more likely to have a history of previous suicidal behaviour, to have a psychiatric diagnosis, and be unemployed. Their parents were more likely to have arrived in the United Kingdom at an older age. In addition, those who attempted suicide were more likely to have been in an inter-racial relationship and to have changed religions. In the second inter-group comparison, the characteristics of Asian and White suicide attempt patients were examined. White attempters were more likely to have mental illness, and were more likely to use alcohol as part of the method of attempted suicide. By contrast, Asian attempters had experienced life events pertaining to relationships, took fewer tablets and yet expressed greater regret at not succeeding in the attempt. CONCLUSIONS: Although numbers are small, social stress and other cultural factors play an important role in the act of deliberate self-harm.

Adolescent↗

PubMed1992

Incidence of verbal comparisons in beginners' books and in metaphor comprehension research: a search for ecological validity.

Explicit verbal comparisons in 53 popular children's books were syntactically and semantically classified. Comparison types found in these books were contrasted with comparisons used as comprehension stimuli in extant developmental research. Although noun-phrase metaphor has been a popular syntactic form in research, it is a rare form in children's literature. Implications for the design of future stimulus sets are discussed.

Book Classification↗

PubMedDate not supplied

Comparative structural and functional analysis of photoreceptor neurons of Rho-/- mice reveal increased survival on C57BL/6J in comparison to 129Sv genetic background.

To explore the possible influence of defined genetic backgrounds on photoreceptor viability and function in mice carrying a targeted disruption of the rhodopsin gene, the severities of retinopathies in Rho-/- mice on C57BL/6J and 129Sv congenic backgrounds were compared by light microscopy and electroretinography and qualitatively by in situ end labeling of DNA in apoptotic photoreceptor nuclei of retinal sections. Cone photoreceptor viability and function were shown to deteriorate more slowly on the C57BL/6J background in comparison to that of the 129Sv, with significantly greater numbers of outer nuclear layer nuclei in the retinas of C57BL/6J mice at 3 and 4 months of age. Both amplitude and waveform features of the ERG were shown to be remarkably different in the two strains, indicating an approximately 6-fold difference in C57BL/6J Rho-/- mice compared to 129Sv Rho-/- mice at 80 days. Thus, in comparison with the 129Sv strain, genetic modifiers appear to constitute a component of the C57BL/6J background, the expression of which significantly protects cone photoreceptors from apoptotic death in a mutation-induced murine retinopathy. The differences in phenotype revealed in this study are sufficient in principle to provide a basis for comparisons to be made between QTLs in light-induced and mutation-induced systems.

Aging↗

PubMed1998

Earned security, daily stress, and parenting: a comparison of five alternative models.

Research suggests that adults who have developed a coherent perspective on their negative, early attachment relationships (i.e., earned secures) do not reenact poor parenting practices with their own children. However, no studies have addressed whether earned secures maintain positive parenting under the pressures of aversive environmental conditions. This study tested five alternative models that predict how earned secures parent under low and high stress in comparison to adults who had a positive upbringing (i.e., continuous secures) and adults who have an incoherent perspective on a troubled childhood (i.e., insecures). Only if earned secures exhibit effective caregiving under high stress, in comparison to the other security groups, can it be assumed that they have broken the intergenerational cycle of poor parenting. The Adult Attachment Interview was used to classify 97 mothers as earned secure, continuous secure, and insecure. Home observations of parenting and maternal self-reports of daily hassles (our stress measure) were obtained when children were 27 months old. Planned comparisons revealed that the diathesis-stress/incoherent present state of mind model most accurately predicted parenting. Thus, under high stress, the earned secures parented equivalently to the continuous secures and more positively than the insecures; under low stress no group differences were obtained. These findings indicate that in a normative sample earned secures break the intergenerational cycle and exhibit resilient parenting even under high stress conditions.

Adult↗

PubMedDate not supplied

Evolution of rescue systems: a comparison between Cologne and Cleveland.

INTRODUCTION: Comparisons of different emergency medical services (EMS) systems often are reduced to simple comparisons between distinct facilities or strategies (e.g., prehospital physician versus paramedic, "scoop and run" versus "stay and play"). METHODS: The EMS systems of similar cities (Cologne and Cleveland) in two different countries (Germany and the United States) are compared. The comparison is seen from the perspective of an evolutionary standpoint that reflects the development of the EMS system in connection with the special environments. Data on rescue times, facilities, and (trauma) outcomes are compared. RESULTS: No statistically significant differences in outcome between the systems were detected. CONCLUSION: Both systems are developed in special environments and are optimized over decades, which explains the similarities in outcome.

Emergency Medical Services↗

PubMed1999

Multiple comparison procedures for simple one-way ANOVA with dependent data.

The independence assumption, although reasonable when examining cross-sectional data using single-factor experimental designs, is seldom verified by investigators. A Monte Carlo type simulation experiment was designed to examine the relationship between true Types I and II error probabilities in six multiple comparison procedures. Various aspects, such as patterns of means, types of hypotheses, and degree of dependence of the observations, were taken into account. Results show that, if independence is violated, none of the procedures control a using the error rate per comparison. At the same time, as the correlation increases, so does the per-comparison power.

Analysis of Variance↗

PubMed2004

Increasing the reliability of ipsative interpretations in neuropsychology: a comparison of reliable components analysis and other factor analytic methods.

Ipsative approaches to neuropsychological assessment typically involve interpreting difference scores between individual test scores. The utility of these methods is limited by the reliability of neuropsychological difference scores and the number of comparisons between scores. The present study evaluated the utility of difference scores using factor analytic methods, including reliable components analysis (RCA), equally weighted composites and individual neuropsychological measures. Data from 1,364 individuals referred for neuropsychological assessment were factor analyzed and the resulting solutions were used to compute composite scores. Reliabilities and confidence intervals were derived for each method. Results indicated that RCA outperformed other factor analytic methods, but produced a slightly different factor structure. Difference scores derived using orthogonal solutions were slightly more reliable than oblique methods, and both were more reliable than those from equally weighted composites and individual measures. Confidence intervals for difference scores were considerably smaller for factor methods relative to those for individual test comparisons, due to the greater reliability of factor based difference scores and the smaller number of comparisons required. These findings suggest that difference scores derived from orthogonal factor solutions, particularly RCA solutions, may improve reliability for clinical assessment purposes.

Adolescent↗

PubMed1999

Logarithmic 3-Band Color Encoding: Robust Method for Display and Comparison of Compositional Maps in Electron Probe X-ray Microanalysis.

: Electron-excited X-ray maps recorded with the scanning electron microscope (SEM)/electron probe X-ray microanalyzer (EPMA) are a major method of presenting compositional information. Digitally recorded maps are processed in a variety of ways to improve the visibility of features. Scaling of the recorded signal to match the 8-bit gray-scale intensity range of a typical computer display system is almost always necessary. Inherent limitations of gray-scale displays have led to other intensity-encoding methods for X-ray maps, including clipping, histogram normalization, and pseudocolor scales. While feature visibility is improved by applying these scales, comparisons among image sets are difficult. Quantitative comparisons must be based on standardized intensities corrected for background to produce intensity ratio (k-value) maps. We have developed a new logarithmic, multiband color-encoding method to view these k-value maps more effectively. Three color bands are defined, starting with a dark primary color and grading to a bright pastel: blue = trace (0.001 to 0.01); green = minor (0.01 to 0.1); and red = major (0.1 to 1.0). Within each band, the color is assigned according to a logarithmic scale that depends on intensity ratio or compositional measurements. Logarithmic multiband color encoding permits direct comparisons of maps, such as maps of different elements in the same field of view or maps of the same element in different areas, because the color scale is identical for all maps.

Journal Article↗

PubMed2007

PET measurement of serotonin transporter occupancy: a comparison of escitalopram and citalopram.

The selective serotonin reuptake inhibitor (SSRI) citalopram (R,S-citalopram) is a racemic compound of two enantiomers. On the basis of in-vitro studies, inhibition of the human serotonin transporter (5-HTT) is achieved by the S-enantiomer (S-citalopram or escitalopram). The aim of the present PET study was to compare 5-HTT occupancy after single equimolar doses (with respect to S-enantiomer) in humans in vivo using R,S-citalopram (20 mg) and S-citalopram (10 mg) using PET and the radioligand [(11)C]MADAM. The design was a single-dose, double-blind, two-way crossover study in eight healthy male subjects. The 5-HTT binding potential at baseline and after single doses of study drugs was used to calculate 5-HTT occupancy in seven brain regions. Serum concentrations of the study drugs were determined in order to calculate the apparent inhibition constant (K(i),(app)), a secondary parameter of interest for the comparison. In all brain regions examined, occupancy was numerically higher after treatment with R,S-citalopram [66+/-19% to 78+/-17% (mean+/-s.d.) depending on the region] than after S-citalopram (59+/-15% to 69+/-13%; overall comparison: F=14.8, d.f.=1, 90, p<0.001). In line with this the apparent inhibition constant was significantly lower for R,S-citalopram than for S-citalopram (overall comparison: F=6.7, d.f.=1, 90, p<0.05). The small but significant difference in occupancy and K(i),(app) found between R,S-citalopram and S-citalopram suggests that not only S-citalopram but also R-citalopram to some degree occupies the 5-HTT in the human brain in vivo.

Adult↗

PubMed2001

Comparison of empirical peak capacities for high-efficiency capillary chromatographic techniques.

Experimental peak capacities for capillary gas chromatography (GC), capillary liquid chromatography (CLC), and capillary electrochromatography (CEC) were compared. To obtain a meaningful comparison, the following constraints were applied. First, the same sample (mixture of alkylbenzenes) was used as a test mixture for all three techniques; second, the same packing material and column diameter were used in CLC and CEC; and third, isothermal conditions were used in GC, while isocratic conditions were used both in CLC and in CEC. Comparison of peak capacities for the same total column efficiency (approximately 36000 plates) showed that the peak capacity of GC is greater than those of the liquid-phase separation techniques. Comparison of CEC and CLC for constant retention factor was also carried out. For this condition, the results depend on the particle size used; for 3-microm porous particles, CEC had a peak capacity larger than CLC due to higher efficiency from the flow profile generated by electroosmotic flow. However, when 1.5-microm nonporous particles were used, the peak capacities were approximately the same for both techniques. The effect of linear velocity on peak capacity was also studied for all three techniques. Practical conditions aimed at increasing peak capacities of liquid-phase separation techniques are discussed.

Journal Article↗