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PubMed2005

What influences participation in genetic carrier testing? Results from a discrete choice experiment.

This study explores factors that influence participation in genetic testing programs and the acceptance of multiple tests. Tay Sachs and cystic fibrosis are both genetically determined recessive disorders with differing severity, treatment availability, and prevalence in different population groups. We used a discrete choice experiment with a general community and an Ashkenazi Jewish sample; data were analysed using multinomial logit with random coefficients. Although Jewish respondents were more likely to be tested, both groups seem to be making very similar tradeoffs across attributes when they make genetic testing choices.

Adult↗

PubMed2005

Sexual behavior of female rats in a multiple-partner preference test.

In this study, sexually experienced female rats were tested in a multiple-partner preference test (MPPT) in which they were allowed to pace their sexual contacts with four sexually active males. Four cylinders, with a small hole through which only the female could move freely from one cylinder to another, were assembled forming in the center an empty compartment. An intact female was placed in the central compartment and a sexually active male in each cylinder. Female sexual behavior was analyzed throughout the estrus cycle in four consecutive days. Each daily test lasted 15 min. The percentage of exits after intromission or ejaculation was significantly higher than the percentage of exits after each mount. The female spent significantly longer time with one of the males. We designated this male as the preferred male (PM). Although in each of the 4 days studied, females spent significantly longer time with the PM, however, the male selected was not the same throughout the estrus cycle. The number of entries into the compartment of the PM was significantly higher and increased around proestrus. Compared to previous studies, pacing behavior was notably lower in the conditions of the MPPT. No significant differences were observed during the estrous cycle concerning the other parameters recorded. The present results suggest that the MPPT could be a good model to study partner preference in the female rat.

Animals↗

PubMed2004

The characteristics and the prognosis for patients presenting with actively bleeding esophageal varices at endoscopy.

BACKGROUND: It remains unresolved whether the prognosis is worse for patients who present with actively bleeding varices at endoscopy compared with those in whom variceal bleeding has stopped. METHODS: Patients with acute esophageal variceal bleeding were enrolled in this study and were divided into two groups: an active bleeding group and an inactive bleeding group. All patients had band ligation shortly after endoscopic examination and underwent elective ligation procedures until the varices were obliterated. Patients were followed for 1 year or until death. Short- and long-term prognoses were compared. RESULTS: The active bleeding group included 54 patients and the inactive bleeding included 251 patients. Initial hemostasis was achieved in 93% in the active group and 99% in the inactive group ( p = not significant). The rate of recurrent variceal bleeding within 30 days was 24% in the active bleeding group vs. 12% in the inactive bleeding group ( p = 0.01); the mortality rates were 18% and 8%, respectively ( p = 0.03 in a single statistical test; however, Bonferroni correction for the multiple testing of data removed this significance). The rate of recurrent variceal bleeding within 1 year was 37% in the active bleeding group and 27% in the inactive bleeding group ( p = 0.06); the mortality rates were 22% and 21%, respectively ( p = not significant). CONCLUSIONS: Whether variceal bleeding is active or inactive at endoscopy, variceal ligation is equally effective for control of bleeding. The rates of recurrent bleeding and mortality at 1 month were significantly higher among patients with active bleeding. However, the mortality rate was similar for both groups at 1 year.

Endoscopy, Gastrointestinal↗

PubMed2001

Mapping quantitative trait loci for milk production traits on ovine chromosome 6.

Spanish Churra sheep were studied in a daughter design for the presence on chromosome 6 of quantitative trait loci (QTL) influencing milk production traits. Eight half-sib families were genotyped for 11 microsatellites and marker-QTL effects analysed using yield deviations (YD) as quantitative measurements for the following traits: milk yield, protein yield, and protein percentage. QTL analysis was performed by interval mapping based on multimarker regression principles. Significance thresholds were estimated through a permutation test followed by a correction for multiple testing. The results suggest a region on ovine chromosome 6, close to the casein cluster, with an influence on milk traits and particularly on protein percentage. These results, the first ones reported for QTL affecting milk traits in sheep, are discussed in relation to data available for cattle, a closely related species.

Animals↗

PubMed2005

A modified bootscan algorithm for automated identification of recombinant sequences and recombination breakpoints.

We have developed a modified BOOTSCAN algorithm that may be used to screen nucleotide sequence alignments for evidence of recombination without prior identification of nonrecombinant reference sequences. The algorithm is fast and includes a Bonferroni corrected statistical test of recombination to circumvent the multiple testing problems encountered when using the BOOTSCAN method to explore alignments for evidence of recombination. Using both simulated and real datasets we demonstrate that the modified algorithm is more powerful than other phylogenetic recombination detection methods and performs almost as well as one of the best substitution distribution recombination detection methods.

Algorithms↗

PubMed1987

The nonstress test.

The NST has been used extensively in the management of high-risk pregnancies and has been a useful preliminary screening test. However, lack of standardization and multiple testing protocols have made comparisons of reports difficult. The high false-positive rate for protocols not extended for long periods have required back-up testing with other biophysical means whenever there is nonreactivity. Continued research is required to define "normal" reactivity. Meanwhile, ongoing investigations in the area of fetal stimulation may be helpful in arousing the non-reactive sleeping fetus. The benefit of the NST is in its simplicity. Busy practitioners can use it in the office, and large testing centers can screen greater numbers of patients in an effective manner. Given a reactive test, a high expectation of normal outcome is warranted. The false-negative rate, however, for diabetes, postdates, and IUGR, warrant twice-weekly testing. Attention to other baseline characteristics, such as bradycardia and minivariables, coupled with sequential NST evaluation should improve NPV by potentially diagnosing compromise earlier.

False Negative Reactions↗

PubMed2004

Assessment of optic nerve head topographic parameters with a confocal scanning laser ophthalmoscope.

AIM: To assess the disc area, age, sex, laterality (side of the eyes) and refractive error dependent differences in optic nerve head topographic parameters in a normal population. METHODS: Optic nerve head topographic analysis of both eyes of 551 healthy Turkish subjects aged 11-75 years (1102 eyes) was performed using a confocal scanning laser ophthalmoscope, the Heidelberg Retinal Tomograph II (HRT II). The effects of disc size, sex, laterality (side of the eyes), age and refractive error on optic nerve head topographic parameters were assessed. Subjects were divided into three different age groups (<30 years, 30-60 years, >60 years) and three different disc area groups (<2.00 mm(2), 2.00-2.25 mm(2), >2.25 mm(2)). Disc area, topography standard deviation and a total of 12 topographic parameters were calculated by HRT II for each subject. Statistical analysis was performed using Student's t-test, multiple regression analysis, Tukey-HSD test, anova and Pearson's correlation coefficient. RESULTS: A total of 543 subjects (298 women and 245 men) were included in the study. The mean disc area of the subjects was 2.12 +/- 0.47 mm(2) (range 1.16-4.98 mm(2)). The mean refractive error of the subjects was -0.58 +/- 1.71 D (range -4.75 D to +4.25 D). The mean cup shape measure was -0.21 +/- 0.07 (95% confidence interval -0.07 to -0.35). The disc area was significantly correlated with all of the topographic parameters but two; namely, the cup shape measure and the height variation contour. Significant age-related differences were detected in four parameters (mean retinal nerve fibre layer [RNFL] thickness, disc area, cup-to-disc area ratio, cup area) and significant sex-related differences were detected three parameters (mean RNFL thickness, height variation contour, RNFL cross-sectional area). However, there were no significant differences in any of the parameters for laterality and refractive error. The parameter cup shape measure did not correlate with any of the five variables investigated. CONCLUSION: Cup shape measure was the only optic nerve head topographic parameter that was independent of age, sex, disc area, laterality and the refractive error. It seems to be a promising parameter in evaluation and comparison of the optic discs of normal subjects, with different disc area, age, sex, refraction error and laterality, as being independent of the main variation factors of the disc topography.

Adolescent↗

PubMed2001

Prenatal alcohol exposure and childhood behavior at age 6 to 7 years: I. dose-response effect.

OBJECTIVE: Moderate to heavy levels of prenatal alcohol exposure have been associated with alterations in child behavior, but limited data are available on adverse effects after low levels of exposure. The objective of this study was to evaluate the dose-response effect of prenatal alcohol exposure for adverse child behavior outcomes at 6 to 7 years of age. METHODS: Beginning in 1986, women attending the urban university-based maternity clinic were routinely screened at their first prenatal visit for alcohol and drug use by trained research assistants from the Fetal Alcohol Research Center. All women reporting alcohol consumption at conception of at least 0.5 oz absolute alcohol/day and a 5% random sample of lower level drinkers and abstainers were invited to participate to be able to identify the associations between alcohol intake and child development. Maternal alcohol, cigarette, and illicit drug use were prospectively assessed during pregnancy and postnatally. The independent variable in this study, prenatal alcohol exposure, was computed as the average absolute alcohol intake (oz) per day across pregnancy. At each prenatal visit, mothers were interviewed about alcohol use during the previous 2 weeks. Quantities and types of alcohol consumed were converted to fluid ounces of absolute alcohol and averaged across visits to generate a summary measure of alcohol exposure throughout pregnancy. Alcohol was initially used as a dichotomous variable comparing children with no prenatal alcohol exposure to children with any exposure. To evaluate the effects of different levels of exposure, the average absolute alcohol intake was relatively arbitrarily categorized into no, low (>0 but <0.3 fl oz of absolute alcohol/day), and moderate/heavy (>/=0.3 fl oz of absolute alcohol/day) for the purpose of this study. Six years later, 665 families were contacted. Ninety-four percent agreed to testing. Exclusions included children who missed multiple test appointments, had major congenital malformations (other than fetal alcohol syndrome), possessed an IQ >2 standard deviations from the sample mean, or had incomplete data. The Achenbach Child Behavior Checklist (CBCL) was used to assess child behavior. The CBCL is a parent questionnaire applicable to children ages 4 to 16 years. It is widely used in the clinical assessment of children's behavior problems and has been extensively used in research. Eight syndrome scales are further grouped into Externalizing or undercontrolled (Aggressive and Delinquent) behavior and Internalizing or overcontrolled (Anxious/Depressed, Somatic Complaints, and Withdrawn) behaviors. Three syndromes (Social, Thought, and Attention Problems) fit neither group. Higher scores are associated with more problem behaviors. Research assistants who were trained and blinded to exposure status independently interviewed the child and caretaker. Data were collected on a broad range of control variables known to influence childhood behavior and/or to be associated with prenatal alcohol exposure. These included perinatal factors of maternal age, education, cigarette, cocaine, and other substances of abuse and the gestational age of the baby. Postnatal factors studied included maternal psychopathology, continuing alcohol and drug use, family structure, socioeconomic status, children's whole blood lead level, and exposure to violence. Data were collected only from black women as there was inadequate representation of other racial groups. STATISTICAL ANALYSES: Statistical analyses were performed using the SPSS statistical package. Frequency distribution, cross-tabulation, odds ratio, and chi(2) tests were used for analyzing categorical data. Continuous data were analyzed using t tests, analyses of variance (ANOVAs) with posthoc tests, and regression analysis. RESULTS: Testing was available for 501 parent-children dyads. Almost one fourth of the women denied alcohol use during pregnancy. Low levels of alcohol use were reported in 63.8% and moderate/heavy use in 13% of pregnancies. Increasing prenatal alcohol exposure was associated with lower birth weight and gestational age, higher lead levels, higher maternal age, and lower education level, prenatal exposure to cocaine and smoking, custody changes, lower socioeconomic status, and paternal drinking and drug use at the time of pregnancy. Children with any prenatal alcohol exposure were more likely to have higher CBCL scores on Externalizing (Aggressive and Delinquent) and Internalizing (Anxious/Depressed and Withdrawn) syndrome scales and the Total Problem Score. The odds ratio of scoring in the clinical range for Delinquent behavior was 3.2 (1.3-7.6) in children with any prenatal exposure to alcohol compared with nonexposed controls. The threshold dose was evaluated with the 3 prenatal alcohol exposure groups. One-way ANOVA revealed a significant between group difference for Externalizing (Aggressive and Delinquent) and the Total Problem Score. (ABSTRACT TRUNCATED)

Alcohol Drinking↗

PubMed2005

Effects of seasonal climatic conditions on the diagnosis of Mycobacterium avium subspecies paratuberculosis in dairy cattle.

Validity of Johne's disease programs and control protocols that rely on established cut points [e.g., specified sample-to-positive (S/P) ratios] for ELISA serological tests depends on interpreted results that are not susceptible to variable test accuracy. It was hypothesized that seasonal variability exists in serological response to Mycobacterium avium subsp. paratuberculosis (MAP) infection. Further, a reciprocal response may occur, resulting in greater risk of fecal shedding in subclinically infected animals. A testing regimen was invoked that included multiple testing of individual adult cows during the 4 seasons. Serum was collected on a cyclic, monthly basis from 3 randomly selected cohorts of dairy cows, and fecal samples were collected from the 20% of cows with the greatest ELISA test S/P ratios. Staggered, quarterly sampling was continued for 1 yr, and at the conclusion, serum was analyzed en masse. The ELISA outcome values (i.e., S/P ratio) were treated both as categorical and continuous variables. The potential lagged effects of temperature-related seasonality on S/P ratio, as well as the potential for a change in test result caused by temperature were assessed. Results for fecal culture were analyzed on a categorical scale and compared with the ELISA results to explore the possibility of reciprocal fecal shedding. No significant seasonal effects on either S/P ratios or the proportion of cows seropositive to MAP were observed. Furthermore, no evidence was found linking temperature-related seasonality to a reciprocal increase in the risk of fecal culture positivity for MAP.

Animals↗

PubMedDate not supplied

HIV counseling and testing: women's experiences and the perceived role of testing as a prevention strategy.

CONTEXT: It is unclear why women decide to undergo testing for HIV, and how positive and negative testresults impact their sexual behavior. METHODS: A sample of 360 family planning clinic clients in New York City were randomly assigned to receive a four- or eight-week intervention aimed at reducing sexual risk or to serve as controls. Information on their HIV testing experiences was gathered through interviews at baseline and one month, six months and one year after the intervention. RESULTS: At baseline, 67% of women had been tested for HIV. The predominant reason for not being tested was anxiety about the result. Regardless of their testing status at baseline, more than 40% of the women believed that getting tested is a good way to prevent acquiring HIV. Women in the intervention who had been tested multiple times or had last been tested more than six months ago were more likely than women in the control group to initiate HIV testing by the one-month follow-up (relative risk, 2.9 and 6.1, respectively). Rates of mutual testing (being tested at the same time as one's partner) were significantly greater among women who participated in an intervention than among controls at the one-month and six-month interviews. CONCLUSIONS: HIV test counseling must emphasize that testing is not a prevention strategy in and of itself. Mutual testing, although not without risks, offers the safest possible alternative for monogamous couples who choose to forgo condoms.

AIDS Serodiagnosis↗

PubMed1995

Diagnostic information as a commodity.

In estimating the cost-effectiveness of diagnostic procedures, it is helpful to treat diagnostic information as a commodity with a unit price. The amount of useful information provided by a test result can be measured in binary units (bits), and the unit price of the information produced by the test result can be expressed in dollars per bit in much the same way that the price of gold is given in dollars per ounce. This allows comparison of the unit prices of various diagnostic tests, examination of the effect of multiple testing, and calculation of the most cost-effective conditions for screening tests.

Clinical Laboratory Techniques↗

PubMed2003

Global test statistics for treatment effect of stroke and traumatic brain injury in rats with administration of bone marrow stromal cells.

Because no single test measures disability in rats with middle cerebral artery occlusion/traumatic brain injury (MCAo/TBI), multiple tests are needed to assess the effect of bone marrow stromal cell (MSC) on functional recovery. Testing the treatment effect on each outcome at the 0.05 level without adjusting for multiple outcomes can increase type I error. Therefore, we applied the global test to evaluate a common MSC dose effect on multiple outcomes in two applications: (i) MCAo rats with the MSC dose of zero (BPS), 1x10(6) and 3x10(6), and (ii) TBI rats with the MSC dose of zero, 1x10(6), 2x10(6) and 4x10(6), administered intravenously at 1 day after injury. For the MCAo rats, 3x10(6) MSCs improved the 14 day functional recovery (P<0.05) compared to the controls. TBI rats with the MSC dose 4x10(6) were improved significantly at 1 month compared to controls, rats with 1x10(6) or 2x10(6) MSCs (P<0.05). The global test on multiple outcomes is more efficient than a single outcome when treatment effects are consistent. The less correlation among the outcomes, the more power and, therefore, the higher efficiency of the global test. We demonstrated that the global test for continuous outcomes could be implemented under careful statistical modeling and proper data transformation.

Algorithms↗

PubMed2006

Test a clade in phylogenetic trees.

We develop a new method for testing a portion of a tree (called a clade) based on multiple tests of many 4-taxon trees in this paper. This is particularly useful when the phylogenetic tree constructed by other methods have a clade that is difficult to explain from a biological point of view. The statement about the test of the clade can be made through the multiple P values from these individual tests. By controlling the familywise error rate or the false discovery rate (FDR), 4 different tree test methods are evaluated through simulation methods. It shows that the combination of the approximately unbiased (AU) test and the FDR-controlling procedure provides strong power along with reasonable type I error rate and less heavy computation.

Animals↗

PubMed1991

Clinical trials in dementia: learning effects with repeated testing.

The possible confounding role of learning effects during multiple test administration in clinical trials in demented subjects remains uncertain. Seventeen mildly to severely affected patients with Alzheimer's disease (AD) and 16 controls were evaluated with an extensive neuropsychological battery of manually administered and computerized tests. Subjects received 3 weekly sessions using alternate test forms, to mimic a baseline, placebo, and drug condition. Mean scores of AD patients as a group showed no stable improvement, but more subtle learning effects were suggested by an association of dementia severity and change scores in verbal and visual learning. Controls evidenced consistent learning in 3 of 9 tests. These results suggest that clinical trials data from AD patients, especially those with moderately severe impairment, are not contaminated by learning. Degree of cognitive impairment may be related to learning capacity, suggesting caution for learning effects in controls and possibly in patients with mild AD.

Aged↗

PubMed1988

Multiplicity in rehabilitation research: a quantitative assessment.

Recent studies indicate that rehabilitation researchers frequently include multiple tests of significance in their investigations. This study examined the possibility that the Type I error rate in rehabilitation research is inflated due to the inappropriate analysis of data from multiple significance tests. The incidence of Type I error was computed for a sample of rehabilitation research. The results revealed a Type I error assumed level of 5% (p less than .05). The argument is made that methods to determine the rate of Type I error should be routinely used in rehabilitation research.

Periodicals as Topic↗

PubMed2007

Comparison between computer-aided testing and traditional multiple choice: an equivalence study.

AIMS: Computer-aided learning (CAL) is a viable alternative to traditional teaching methods. While CAL is used for teaching only, computer-aided testing (CAT) can be applied as a computer-based examination method. The aim of the present study was to compare the performance of undergraduate students in computer-interactive tests and traditional multiple choice tests and to evaluate the influence of question length and language skills on test results. MATERIALS AND METHODS: Fifty-two native German-speaking students and five non-native speaking students were randomly assigned to two groups. They were required to answer 20 conventional multiple choice questions and 20 questions using the interactive MobiTed system. An analysis of variance and t-tests (alpha = 0.05) were used to compare scores. RESULTS: Non-native speakers scored significantly lower on the interactive test compared with the native speaking students (P = 0.048 for long questions and P = 0.003 for short questions). There were no significant group differences on the conventional multiple choice test (P = 0.052 for long questions and P = 0.089 for short questions). Based on the results of the native speaking students neither test method nor question length had an influence on overall performance. CONCLUSION: Interactive multiple choice tests may provide an alternative to written tests, especially when considering time expenditure. Language skills and question length should be taken into account when setting time limits for examination.

Computer-Assisted Instruction↗

PubMed2005

Selection of single-nucleotide polymorphisms in disease association data.

We studied several methods for selecting single-nucleotide polymorphisms (SNPs) in a disease association study. Two major categories for analytical strategy are the univariate and the set selection approaches. The univariate approach evaluates each SNP marker one at a time, while the set selection approach tests disease association of a set of SNP markers simultaneously. We examined various test statistics that can be utilized in testing disease association and also reviewed several multiple testing procedures that can properly control the family-wise error rates when the univariate approach is applied to multiple markers. The set association methods were then briefly reviewed. Finally, we applied these methods to the data from Collaborative Study on the Genetics of Alcoholism (COGA).

Databases, Genetic↗

PubMed1983

[Value of MS associated factors for test procedures in multiple sclerosis: 2. Angers' MS-induced substance in the LAI test].

Attempts to find test systems specific for multiple sclerosis are directed to the investigation of MS-associated factors in serum. Basing on the methods of the adherence of antigen-reactive leukocytes, the MSRM (MS-related material) a substance conditioned by the disease was derived from blood of MS-patients and applied in the leukocyte adherence-inhibition (LAI)-test. The mean values in the LAI-test showed a significant difference between MS, the other neurological diseases (OND) and the normals. For the limiting value mean NK +/- 2 s a positive LAI-effect resulted in 58% of the intermittent and in 43% of the chronic-progredient cases of MS, yet also in 11% of the OND. The fact that the rate of detection is lower than that reported by Angers, could depend on factors caused by the method used or by anomalies of immune regulation in MS (including the so-called blocking factors in serum). The results received with LAI-test applying the MSRM don't allow any definite diagnostical assessment specific for MS.

Antigens, Viral↗