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Prenatal Diagnosis Dec 2009Current risk calculations for trisomy 21, which are based on multiples of median (MoM), do not take into account possible differences between euploid and trisomy 21... (Comparative Study)
Comparative Study
BACKGROUND
Current risk calculations for trisomy 21, which are based on multiples of median (MoM), do not take into account possible differences between euploid and trisomy 21 pregnancies that may develop with gestational age. In order to optimize the predictive value of screening tests, we calculated the ratio between maternal serum concentration of alpha-fetoprotein (AFP) and that of human chorionic gonadotropin (hCG) in euploid and in trisomy 21 pregnancies.
METHODS
The medians of the concentration ratios, [AFP]/[hCG] at 16-21 weeks of gestation, were plotted as a function of gestational age for 307 cases of trisomy 21 and were compared with the medians of 30 549 normal karyotype cases.
RESULTS
[AFP]/[hCG] ratio medians were independent of body weight and maternal age. There was a significant difference in the [AFP]/[hCG] ratio when comparing trisomy 21 and euploid pregnancies at each week. This difference became greater with advancing gestational age (P < 0.01).
CONCLUSION
There is a significant difference in ratios of [AFP]/[hCG] between euploid and trisomy 21 pregnancies, which may be used to improve detection rates of Down syndrome screening.
Topics: Adult; Chorionic Gonadotropin; Down Syndrome; Female; Gestational Age; Humans; Mothers; Ploidies; Pregnancy; Prenatal Diagnosis; Retrospective Studies; Sensitivity and Specificity; alpha-Fetoproteins
PubMed: 19777489
DOI: 10.1002/pd.2366 -
Pharmaceutical Statistics 2010The Hodges-Lehmann estimator was originally developed as a non-parametric estimator of a shift parameter. As it is widely used in statistical applications, the question...
The Hodges-Lehmann estimator was originally developed as a non-parametric estimator of a shift parameter. As it is widely used in statistical applications, the question is investigated what it is estimating if the shift model does not hold. It is shown that for data whose distributions are symmetric about their median the Hodges-Lehmann estimator based on the Wilcoxon Rank Sum test estimates the difference between the medians of the distributions. This result does generally not hold if the symmetry assumption is violated.
Topics: Data Interpretation, Statistical; Models, Statistical; Statistics, Nonparametric; Survival Analysis
PubMed: 19718773
DOI: 10.1002/pst.387 -
Biological Trace Element Research Jul 2023The objective of this study was to establish a reference interval for serum zinc in dogs and to determine the factors that affected it. We collected samples from 197...
The objective of this study was to establish a reference interval for serum zinc in dogs and to determine the factors that affected it. We collected samples from 197 clinically healthy animals of various breeds and ages and obtained information about their sex, neuter status, age, breed, diet, lifestyle, weight, and body condition score. Serum zinc concentration was measured by a colorimetric method using a clinical chemistry analyzer. We established the reference interval for serum zinc as 4.9-19.7 µmol/L. When assessing the relationship of zinc with various biochemical parameters, we found significant correlation with albumin and triacylglycerols. The only observed factor that significantly influenced serum concentration was sex. Female dogs had higher levels (median 11.0 µmol/L) than males (median 8.9 µmol/L). The difference between intact females and intact males was also significant (medians 11.6 and 9.0 µmol/L respectively), but it was only numerical for neutered animals (median of neutered females 10.7 µmol/L and of neutered males 8.7 µmol/L). Despite the general belief that homemade food for dogs contains a lower amount of zinc than a commercial one, diet did not influence zinc serum levels significantly. There was also no impact of age, breed, lifestyle, weight, or body condition score on serum zinc concentration.
Topics: Male; Dogs; Female; Animals; Serum; Zinc; Health Status
PubMed: 36224317
DOI: 10.1007/s12011-022-03441-x -
Traffic Injury Prevention 2021Different design alternatives used to separate freeway-opposing traffic may produce varying safety levels. State-of-the-art design guidelines have provided guidance in...
OBJECTIVES
Different design alternatives used to separate freeway-opposing traffic may produce varying safety levels. State-of-the-art design guidelines have provided guidance in respect to a number of median features such as width, slope, and barrier installation. Guidance provided has been based on benefit-cost procedures; however, because project costs may significantly vary across different countries/jurisdictions, findings from benefit-cost procedures may be meaningless on a broader geographical scope. The objective of this study is to quantify the safety level of a number of design alternatives commonly used to separate opposing freeway traffic based solely on annualized crash costs.
METHODS
The safety performance of 14 design alternatives were assessed using the Roadside Safety Analysis Program (RSAPv3).
RESULTS
A test-level 3, low-tension cable barrier installed in the middle of a wide, hazard-free median was found to be the safest design alternative. Road sections containing: i) cable barriers were found to be safer than those containing w-beam guardrails, ii) low-tension cable barriers installed in the middle of the median were found to be safer than those containing high-tension cable barriers installed on one side of the median, regardless of median width, iii) wide, hazard-free medians were found to be safer than those containing WB guardrails, and iv) concrete barrier installations were found to be only safer than those containing unshielded medians, except when the median was 20 meters wide and hazard-free.
CONCLUSIONS
This paper not only provides evidence that some of the design alternatives often installed in real-world scenarios are not the safest, but it also discusses how some of these alternatives may not be the most cost-effective either. These findings make this study relevant and timely, as designers and policy/decision makers should always seek to maximize safety while optimizing the allocation of limited public funds.
Topics: Accidents, Traffic; Emotions; Environment Design; Humans; Safety
PubMed: 34432602
DOI: 10.1080/15389588.2021.1965591 -
Advances in Skin & Wound Care Aug 2022To analyze the blood oxygen concentrations (StO 2 ) of different stages of pressure injury (PI) tissue using hyperspectral images to serve as a guideline for the...
OBJECTIVE
To analyze the blood oxygen concentrations (StO 2 ) of different stages of pressure injury (PI) tissue using hyperspectral images to serve as a guideline for the treatment and care of PIs.
METHODS
This study used a prospective design. A total of 30 patients with sacral PIs were recruited from the rehabilitation ward of a teaching hospital. The authors used a hyperspectral detector to collect wound images and the Beer-Lambert law to estimate changes in tissue StO 2 in different stages of PI.
RESULTS
The tissue StO 2 of healthy skin and that of stage 1 PI skin were similar, whereas the tissue StO 2 of the wound in stage 2 PIs was significantly higher than that of healthy skin and scabbed tissue (medians, 82.5%, 74.4%, and 68.3%; P < .05). In stage 3 PIs, StO 2 was highest in subcutaneous tissue and adipose tissue (82.5%) and lowest in peripheral scabs (68.35%). The tissue StO 2 was highest in subcutaneous tissue in stage 4 PIs, and this tissue was red in the hyperspectral spectrum. The scab-covered area of unstageable PIs had the lowest StO 2 of all PI tissue types (median, 44.3%).
CONCLUSIONS
Hyperspectral imaging provides physiologic information on wound microcirculation, which can enable better evaluation of healing status. Assessing tissue StO 2 data can provide a clinical index of wound healing.
Topics: Humans; Hyperspectral Imaging; Microcirculation; Prospective Studies; Skin; Wound Healing; Pressure Ulcer
PubMed: 35819937
DOI: 10.1097/01.ASW.0000831888.39420.a6 -
Anesthesia and Analgesia Sep 2013When a study uses an ordinal outcome measure with unknown differences in the anchors and a small range such as 4 or 7, use of the Wilcoxon rank sum test or the Wilcoxon... (Review)
Review
When a study uses an ordinal outcome measure with unknown differences in the anchors and a small range such as 4 or 7, use of the Wilcoxon rank sum test or the Wilcoxon signed rank test may be most appropriate. However, because nonparametric methods are at best indirect functions of standard measures of location such as means or medians, the choice of the most appropriate summary measure can be difficult. The issues underlying use of these tests are discussed. The Wilcoxon-Mann-Whitney odds directly reflects the quantity that the rank sum procedure actually tests, and thus it can be a superior summary measure. Unlike the means and medians, its value will have a one-to-one correspondence with the Wilcoxon rank sum test result. The companion article appearing in this issue of Anesthesia & Analgesia ("Aromatherapy as Treatment for Postoperative Nausea: A Randomized Trial") illustrates these issues and provides an example of a situation for which the medians imply no difference between 2 groups, even though the groups are, in fact, quite different. The trial cited also provides an example of a single sample that has a median of zero, yet there is a substantial shift for much of the nonzero data, and the Wilcoxon signed rank test is quite significant. These examples highlight the potential discordance between medians and Wilcoxon test results. Along with the issues surrounding the choice of a summary measure, there are considerations for the computation of sample size and power, confidence intervals, and multiple comparison adjustment. In addition, despite the increased robustness of the Wilcoxon procedures relative to parametric tests, some circumstances in which the Wilcoxon tests may perform poorly are noted, along with alternative versions of the procedures that correct for such limitations.
Topics: Algorithms; Analgesics, Opioid; Anesthesiology; Confidence Intervals; Data Interpretation, Statistical; Humans; Models, Statistical; Postoperative Nausea and Vomiting; Randomized Controlled Trials as Topic; Research Design; Sample Size; Teaching Rounds
PubMed: 23456667
DOI: 10.1213/ANE.0b013e31827f53d7 -
Journal of Clinical Pathology Jun 2006To establish gestational age-specific mid-trimester normal medians for the prenatal serum markers alpha fetoprotein (AFP), human chorionic gonadotropin (HCG) and...
OBJECTIVES
To establish gestational age-specific mid-trimester normal medians for the prenatal serum markers alpha fetoprotein (AFP), human chorionic gonadotropin (HCG) and unconjugated oestriol (uE3) for a Belgian population by using the Beckman Coulter Access chemiluminiscent immunoassays; to compare these data with data obtained from other geographical regions; to propose regression coefficients for regressed medians and analyse variation induced by different regression equations; to evaluate the effect of formulas used for gestation correction on estimating risk in Down's syndrome.
DESIGN
Data derived from 862 fresh serum samples from women being screened for Down's syndrome pregnancy, composed of selected pregnancies deemed to be normal, were examined in a retrospective study. Regressed medians were calculated by using a first-degree logarithmic-linear fit of the raw data. Multiples-of-median (MoM) values estimated by using a simple logarithmic-linear equation were compared with those calculated with higher-degree polynomials chosen with a goodness-of-fit analysis. Model-specific variation was estimated and the effect on risk for Down's syndrome was evaluated.
RESULTS
Regressed medians (Y) for Access serum markers AFP (IU/ml), HCG (IU/ml) and uE3 (nmol/l) for a Belgian population can be estimated with the equation Y = 10((A+BX)) with X = decimal weeks. The best fit was obtained with a third-degree and a second-degree polynomial for AFP and uE3, respectively. Differences between the medians and among the slopes of the geographical populations were found to be significant (analysis of covariance, p<0.001).
CONCLUSIONS
Belgian marker medians versus gestational time are found to show a pattern that is similar to that in the literature. The log-linear equation is observed to give a good fit and can be suggested as a tool for calculating median MoM values for Belgian laboratories that use Access biochemical prenatal markers.
Topics: Belgium; Biomarkers; Canada; Chorionic Gonadotropin; Down Syndrome; Epidemiologic Methods; Estriol; Female; Fetal Diseases; Gestational Age; Humans; Pregnancy; Pregnancy Trimester, Second; Prenatal Diagnosis; Reference Values; United Kingdom; United States; alpha-Fetoproteins
PubMed: 16731605
DOI: 10.1136/jcp.2005.034272 -
Objective User Engagement With Mental Health Apps: Systematic Search and Panel-Based Usage Analysis.Journal of Medical Internet Research Sep 2019Understanding patterns of real-world usage of mental health apps is key to maximizing their potential to increase public self-management of care. Although developer-led...
BACKGROUND
Understanding patterns of real-world usage of mental health apps is key to maximizing their potential to increase public self-management of care. Although developer-led studies have published results on the use of mental health apps in real-world settings, no study yet has systematically examined usage patterns of a large sample of mental health apps relying on independently collected data.
OBJECTIVE
Our aim is to present real-world objective data on user engagement with popular mental health apps.
METHODS
A systematic engine search was conducted using Google Play to identify Android apps with 10,000 installs or more targeting anxiety, depression, or emotional well-being. Coding of apps included primary incorporated techniques and mental health focus. Behavioral data on real-world usage were obtained from a panel that provides aggregated nonpersonal information on user engagement with mobile apps.
RESULTS
In total, 93 apps met the inclusion criteria (installs: median 100,000, IQR 90,000). The median percentage of daily active users (open rate) was 4.0% (IQR 4.7%) with a difference between trackers (median 6.3%, IQR 10.2%) and peer-support apps (median 17.0%) versus breathing exercise apps (median 1.6%, IQR 1.6%; all z≥3.42, all P<.001). Among active users, daily minutes of use were significantly higher for mindfulness/meditation (median 21.47, IQR 15.00) and peer support (median 35.08, n=2) apps than for apps incorporating other techniques (tracker, breathing exercise, psychoeducation: medians range 3.53-8.32; all z≥2.11, all P<.05). The medians of app 15-day and 30-day retention rates were 3.9% (IQR 10.3%) and 3.3% (IQR 6.2%), respectively. On day 30, peer support (median 8.9%, n=2), mindfulness/meditation (median 4.7%, IQR 6.2%), and tracker apps (median 6.1%, IQR 20.4%) had significantly higher retention rates than breathing exercise apps (median 0.0%, IQR 0.0%; all z≥2.18, all P≤.04). The pattern of daily use presented a descriptive peak toward the evening for apps incorporating most techniques (tracker, psychoeducation, and peer support) except mindfulness/meditation, which exhibited two peaks (morning and night).
CONCLUSIONS
Although the number of app installs and daily active minutes of use may seem high, only a small portion of users actually used the apps for a long period of time. More studies using different datasets are needed to understand this phenomenon and the ways in which users self-manage their condition in real-world settings.
Topics: Anxiety; Depression; Humans; Mental Disorders; Mental Health; Mobile Applications; Self-Management; Telemedicine
PubMed: 31573916
DOI: 10.2196/14567 -
The American Journal of Sports Medicine Jul 2017The anterior cruciate ligament (ACL) is regularly reconstructed if knee joint function is impaired. Anatomic graft tunnel placement, often assessed with varying... (Review)
Review
The Anatomic Centers of the Femoral and Tibial Insertions of the Anterior Cruciate Ligament: A Systematic Review of Imaging and Cadaveric Studies Reporting Normal Center Locations.
BACKGROUND
The anterior cruciate ligament (ACL) is regularly reconstructed if knee joint function is impaired. Anatomic graft tunnel placement, often assessed with varying measurement methods, in the femur and tibia is considered important for an optimal clinical outcome. A consensus on the exact location of the femoral and tibial footprint centers is lacking.
PURPOSE
To systematically review the literature regarding anatomic centers of the femoral and tibial ACL footprints and assess the mean, median, and percentiles of normal centers.
STUDY DESIGN
Systematic review.
METHODS
A systematic literature search was performed in the PubMed/Medline database in November 2015. Search terms were the following: "ACL" and "insertion anatomy" or "anatomic footprint" or "radiographic landmarks" or "quadrant methods" or "tunnel placement" or "cadaveric femoral" or "cadaveric tibial." English-language articles that reported the location of the ACL footprint according to the Bernard and Hertel grid in the femur and the Stäubli and Rauschning method in the tibia were included. Weighted means, weighted medians, and weighted 5th and 95th percentiles were calculated.
RESULTS
The initial search yielded 1393 articles. After applying the inclusion and exclusion criteria, 16 studies with measurements on cadaveric specimens or a healthy population were reviewed. The weighted mean of the femoral insertion center based on measurements in 218 knees was 29% in the deep-shallow (DS) direction and 35% in the high-low (HL) direction. The weighted median was 26% for DS and 34% for HL. The weighted 5th and 95th percentiles for DS were 24% and 37%, respectively, and for HL were 28% and 43%, respectively. The weighted mean of the tibial insertion center in the anterior-posterior direction based on measurements in 300 knees was 42%, and the weighted median was 44%; the 5th and 95th percentiles were 39% and 46%, respectively.
CONCLUSION
Our results show slight differences between the weighted means and medians in the femoral and tibial insertion centers. We recommend the use of the 5th and 95th percentiles when considering postoperative placement to be "in or out of the anatomic range."
Topics: Anterior Cruciate Ligament; Anterior Cruciate Ligament Injuries; Anterior Cruciate Ligament Reconstruction; Databases, Factual; Femur; Humans; Tibia
PubMed: 27899355
DOI: 10.1177/0363546516673984 -
Revue Belge de Medecine Dentaire.... 1970
Topics: Dentition; Diastema; Humans; Tooth Extraction
PubMed: 5273768
DOI: No ID Found