Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “association testing”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

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

At least 469 records · Page 26Linked to original sources
PubMed1979

Effects of personality and loss of anonymity on aggression: a reevaluation of deindividuation.

Zimbardo's deindividuation hypothesis was reexamined by individuating some subjects. Twelve four-person groups administered shock to a confederate in a 2 x 2 x 2 factorial design with two levels of social individuation (subjects' level of anonymity to group members), two levels of nonsocial individuation (subjects' opportunity to give identifying information to the experimenter on a word association test) and two levels of individual differences. It was found that subjects, who individuated themselves by giving information to the experimenter on the word association test showed more, not less, antisocial behavior. Furthermore, this increased antisocial behavior was exhibited only by externally oriented subjects: those with an external locus of control and a low mysticism score. Some of those more antisocial subjects were also more likely to report feeling like they stood out from the group. It was concluded that antisocial behavior in this paradigm may thus be a response to experimenter demand felt most strongly when subjects felt most identifiable.

Aggression↗
PubMed1986

Tests of association of immunoglobulin allotype genes and viral oncogenesis in chickens.

Chickens from Regional Poultry Research Laboratory (RPRL) inbred line 6(3) are resistant to virally-induced Marek's disease (MD) and lymphoid leukosis (LL) and are relatively strong regressors of virally-induced Rous sarcomas. In contrast, RPRL line 100 chickens are highly susceptible to MD and LL and are weaker regressors of Rous sarcomas than line 6(3). RPRL lines 100 and 6(3) differ for alleles at the IgG-1 (G-1) allotype locus, but have identical IgM-1 (M-1) allotype alleles. To test the possible association of the G-1 locus with variations in resistance to virally-induced tumors, homozygous and heterozygous genotypes among F3 crosses were infected. F3 chickens with different G-1 types were comparable in their resistance to MD tumors following inoculation with the JM strain of the MD virus, and for their ability to regress Rous sarcoma tumors induced by the Rous sarcoma virus (RSV) RAV-1. However, following RAV-1 virus infection a smaller proportion of G-1a/G-1aF3 or F4 birds developed LL tumors than G-1a/G-1e and G-1e/G-1e birds. Genes determining immunoglobulin heavy chains were therefore associated with a recessive resistance to B-cell lymphomagenesis in chickens.

Animals↗
PubMed2002

Fine tuning of the digit symbol paired associate recall test for practitioner purposes in clinical and research settings.

Guidelines are presented to facilitate the use of the WAIS Digit Symbol measure of paired associate recall as a neuropsychological instrument. Currently three formal variants of the test exist with accompanying normative data (the original WAIS-R-NI form; a WAIS-R Short Form; a longer WAIS-III form), providing a potential source of confusion which may limit its application. To circumvent this, the present article critically evaluates: (i) variations in test forms and their advantages; (ii) available norms in terms of age and education, with pointers for more differentiated guidelines in this regard; and (iii) the desirability of incorporating a delayed recall variant of the test. Finally, a synopsis of data is presented that supports the screening potential of Digit Symbol paired associate recall in cases of mild neurocognitive dysfunction. For the purposes of this paper, the term WAIS is used with broad reference to all variations of the original Wechsler Adult Intelligence Scale (1955) upon which they were based, including the WAIS-R (1981) and WAIS-III (1997) updated editions, and the South African WAIS (1969). The terms South African WAIS (South African Wechsler Adult Intelligence Scale), WAIS-R (Wechsler Adult Intelligence Scale - Revised), and WAIS-III (Wechsler Adult Intelligence Scale-III), refer to these specific versions of the test.

Adult↗
PubMed1993

Compatibility testing problems associated with bovine thrombin-treated plasma.

Plasma converted to serum by the addition of bovine thrombin prior to compatibility testing agglutinated all donor red cells. This finding prompted an investigation of bovine thrombin- associated incompatibility that showed that (1) thrombin derived from bovine plasma contains IgG antibodies directed against all human red cells, and (2) excess (> 50 units/mL) bovine thrombin used for conversion of plasma to serum may cause hemagglutination and erroneous serologic test results because of the presence of heteroagglutinins.

Journal Article↗
PubMed1997

Auditory P300 topography and neuropsychological test performance: evidence for left hemispheric dysfunction in schizophrenia.

Asymmetrical topography of the auditory P300 with reduced left hemispheric amplitudes and, consequently, a right-lateralized peak of the P300 electrical field has been repeatedly reported in schizophrenia. This was interpreted as an indication of reduced left-hemispheric activity during the simple cognitive P300 task. Since generator locations calculated from the surface potentials are ambiguous, further evidence is required to support this conclusion. In the present study, 13 stabilized DSM-III-R schizophrenic patients were studied with an auditory P300 paradigm and neuropsychological methods sensitive to functional brain asymmetries. The tests included the verbal paired associates test (Goldstein et al 1988, Cortex 24:41-52) and the nonspatial conditional associative learning test (Petrides 1985, Neuropsychologia 23:601-614). A significant correlation was found between right-sided lateralization of the P300 maximal positivity and neuropsychological evidence for left hemispheric temporal- hippocampal dysfunction. Attentional performance was correlated with P300 amplitudes. The results of this study provide further evidence that right-sided lateralization of the P300 peaks results from dysfunction of left-hemispheric neuronal generators.

Acoustic Stimulation↗
PubMed1990

The state of the testicle and the epididymis associated with exstrophy of the bladder in undescended testes.

In undescended tests, the large number of testicular dysplasias/hypoplasias and of that of the fusion abnormalities of the epididymis, and the joint occurrence of the two, can achieve even 50%. The frequency of the above anomalies were studied in undescended testes associated with exstrophy of the bladder. Bilateral undescended testes were observed in 5 out of 26 boys born with vesical exstrophy. In 3 of them bilateral orchiopexy had already been performed. In 5 of the 6 operations intact testicles and intact epididymis were found. Fusion abnormality was observed only in one case, but the testicle was intact also in that case. This can be attributed to the fact that in exstrophy of the bladder, the testicles have failed to descend not due to the insufficient effect of fetal androgen, but due to anatomical causes. This is also supported by the fact that where the disorder of descension has been caused by mechanical factors, there was a much lower ratio of testicular-epididymal fusion abnormality.

Bladder Exstrophy↗
PubMed2003

Tests of candidate genes in breed cross populations for QTL mapping in livestock.

In recent years, several F(2) crosses between outbred lines of livestock have been developed to identify quantitative trait loci (QTL). These populations are valuable for further genetic analysis, including positional candidate gene loci (CGL). Analysis of CGL in F(2) populations is, however, hindered by extensive between-breed linkage disequilibrium (LD). The objectives here were to develop and evaluate three tests for CGL in simulated F(2) breed-cross populations. 1) A standard association test, based on the fixed effect of CGL genotype. This test was significant for CGL at considerable distances from the QTL. 2) A marker-assisted association test, based on a test at the CGL of the fixed effect of CGL genotype in a breed-cross QTL interval mapping model. This removed the impact of between-breed LD, but was not powerful in detecting CGL closely linked to the QTL, unless the CGL was the QTL. 3) An F-drop test, comparing F ratios for a QTL at the CGL with and without the CGL included as fixed effect. It had low power to distinguish close from distant CGL. Power to distinguish two CGL within 10 cM from the QTL was limited and little improved by including QTL effects associated with markers to remove between-breed LD, although the power was greater when one of the CGL was the causative mutation. Therefore, while we conclude that candidate gene tests in QTL mapping populations must be interpreted with caution, we now have a clearer picture of the value of candidate gene tests in these populations.

Animals↗
PubMed2002

Homocysteine, B vitamin status, and cognitive function in the elderly.

BACKGROUND: Old age is associated with reduced cognitive performance. Nutritional factors may contribute to this association. OBJECTIVE: We tested associations between cognitive performance and plasma vitamin B-12, folate, and homocysteine concentrations in the elderly. DESIGN: We studied survivors of the Scottish Mental Surveys of 1932 (Aberdeen 1921 Birth Cohort, or ABC21) and 1947 (Aberdeen 1936 Birth Cohort, or ABC36), which surveyed childhood intelligence quotient. We measured folate, vitamin B-12, and homocysteine concentrations in fasting blood samples and cognitive performance by the Mini Mental State Examination (MMSE), National Adult Reading Test (NART), Raven's Progressive Matrices (RPM), Auditory Verbal Learning Test (AVLT), digit symbol (DS) subtest, and block design (BD) subtest. RESULTS: Homocysteine was higher in the ABC21 than in the ABC36 (P < 0.0001). There were positive correlations between folate and vitamin B-12 and negative correlations between homocysteine and both folate and vitamin B-12. MMSE, RPM, AVLT, DS, and BD scores were higher in the ABC36. In the ABC21, folate, vitamin B-12, and MMSE score were positively correlated and homocysteine was negatively correlated with RPM, DS, and BD scores. Folic acid was positively correlated with AVLT and DS scores. In the ABC36, folate was positively correlated with BD score. After adjustment for childhood intelligence quotient, partial correlations were strengthened between vitamin B-12 and NART score and between homocysteine and RPM score but weakened between red blood cell folate and DS score. CONCLUSIONS: B vitamins and homocysteine are associated with cognitive variation in old age. In the ABC21 but not the ABC36, homocysteine accounted for approximately 7-8% of the variance in cognitive performance. This may prove relevant to the design of neuroprotective studies in late life.

Aged↗
PubMed1999

Early pregnancy prenatal diagnostic testing: risks associated with chorionic villus sampling and early amniocentesis and screening options.

Routine amniocentesis is an established test for the prenatal diagnosis of chromosome abnormalities and many single-gene conditions. Chorionic villus sampling and early amniocentesis, which are available in some centers, enable families to receive prenatal test results earlier in the pregnancy. There are concerns regarding the safety of early pregnancy testing because of increased risks for pregnancy loss and possible risks for birth defects. The use of first trimester testing has changed because of these concerns, and alternative methods of screening pregnancies at risk for a chromosome abnormality are being investigated.

Adult↗
PubMed1990

Laboratory costing system based on number and type of test: its association with the Welcan workload measurement system.

A laboratory costing system which recovers all costs against tests, rather than using both test and request charges, was developed. Methods of recovering costs of routine and emergency services, of capital investment in equipment, of instrument maintenance costs and of general hospital overheads were considered. The Welcan unit system of workload measurement was applied to a range of test procedures. Both the Welcan unit value and unit value adjusted fro calibration and quality control (Welcan based weighting) correlated only moderately with locally derived analytical time per test and correlated poorly with direct analytical cost per test. The correlation of direct analytical cost per test with total cost per test was much stronger than that of analytical time per test with direct analytical cost per test. The data suggest that neither Welcan unit values, Welcan based weightings, nor locally derived analytical time per test can truly reflect total resource consumption for the provision of a range of test procedures. This factor should be borne in mind when applying operational or performance indicators based on Welcan units.

Clinical Laboratory Techniques↗
PubMed2002

Analysis of the RNASEL gene in familial and sporadic prostate cancer.

The RNASEL gene on chromosome 1q25 was recently identified as a candidate gene for hereditary prostate cancer (PC). To confirm these findings, we screened 326 patients from 163 families with familial PC for potential germline mutations, by use of conformation-sensitive gel electrophoresis, followed by direct sequence analysis. A total of six variants were identified, including one intronic and five exonic changes (three missense and two silent alterations). There were no unequivocal pathogenic changes. To further test for potential associations between genes and increased risk for disease, the three missense polymorphisms (Ile97Leu, Arg462Gln, and Glu541Asp) were genotyped in 438 patients with familial PC and in 510 population-based control subjects. Association testing revealed no significant differences between patients and control subjects for either the Leu97 variant (chi(2) trend test = 1.42; P=.23) or the Asp541 variant (chi2=1.52; P=.22). However, significant differences were detected for the Arg462Gln genotypes (chi2=5.20; P=.02; odds ratio [OR] = 0.54; 95% confidence interval [CI] 0.32-0.91) when the genotype Gln/Gln was compared with Arg/Arg. In subset analyses, associations were also observed in the younger group (age at diagnosis </=64 years) (P=.0008; OR=0.29; 95% CI = 0.13-0.66), in node-negative patients (P=.01; OR=0.48; 95% CI 0.27-0.84), patients with stage T(1)/T(2) disease (P=.008; OR=0.39; 95% CI 0.2-0.75), and patients with low-grade disease (P=.01; OR=0.40; 95% CI 0.20-0.78). To evaluate whether this variant was also associated with sporadic PC, we genotyped an additional 499 patients with sporadic PC. Differences in frequency were not detected between patients with sporadic disease and control subjects. However, the same association was observed between patients with familial disease and patients with sporadic disease for the entire group (chi2=4.82; P=.03), as well as in the subset analyses. These results suggest that polymorphic changes within the RNASEL gene may be associated with increased risk of familial but not sporadic PC.

Adult↗
PubMed2006

Comparison of accuracy of transabdominal ultrasonography, progesterone and pregnancy-associated glycoproteins tests for discrimination between single and multiple pregnancy in sheep.

The aim of the present study was to evaluate and, compare the accuracy of transabdominal ultrasonographic (US) and the progesterone (P4-RIA) and ovine pregnancy-associated glycoprotein (ovPAG-RIA) tests for the discrimination between single and multiple pregnancy in sheep. One hundred pregnant AwassixMerino ewes were scanned by transabdominal ultrasonography (3.5 MHz linear-array transducer) at Days 43-56 and 81 of these ewes were scanned at Days 76-87 of gestation. The ewes were scanned in dorsal recumbency at the bare area of the inguinal regions (without pre-scanning shaving of the ventral abdominal wall). After each scan, blood samples were withdrawn from the jugular vein to estimate the levels of P4 and ovPAG by radioimmunoassay. At lambing, 61 ewes gave birth to single lambs and 39 ewes gave birth to multiples. The sensitivity of the transabdominal US, the P4-RIA and the ovPAG-RIA tests for determining ewes carrying multiples was 54, 64.1 and 64.1% at Days 43-56. At Days 76-87 of gestation these accuracies were 60.0, 66.7 and 76.6% for the US, P4-RIA and PAG-RIA tests, respectively. The specificity of the transabdominal US, the P4-RIA and the ovPAG-RIA tests for determining ewes carrying singles, was 78.6, 60.7 and 62.3% at Days 43-56 and 78.4, 64.7 and 70.6% at Days 76-87 of gestation, respectively. It is concluded that the accuracy of transabdominal ultrasonographic (without pre-scanning shaving of the ventral abdominal wall), the P4- and the ovPAG-RIA tests for determination of the fetal numbers in AwassixMerino crossbred ewes is too low to be used in the field.

Animals↗
PubMed2005

Factors associated with HIV testing, condom use, and sexually transmitted infections among female sex workers in Nha Trang, Vietnam.

This study examined predictors of HIV testing, successful condom negotiation with clients, and self-reported sexually transmitted infections (STIs) among Vietnamese female sex workers (FSW). Data were collected by using face-to-face interviews from a community sample of 610 FSW from Nha Trang city during October-December, 2000. Having had an HIV test was associated with having spent time in a rehabilitation center. Consistently successful negotiation of condom use occurred most among FSW who had few clients, understood how HIV was not transmitted, and had not reported ever having any symptoms of STIs. Migration to Nha Trang for sex work was a risk factor for an STI diagnosis; successful negotiation of condom use had a protective effect. Our results suggest the need for voluntary HIV counseling and testing, further promotion of condom use among FSW populations, and better use of rehabilitation sites to promote HIV prevention.

AIDS Serodiagnosis↗
PubMed2004

The future of association studies: gene-based analysis and replication.

Historically, association tests were limited to single variants, so that the allele was considered the basic unit for association testing. As marker density increases and indirect approaches are used to assess association through linkage disequilibrium, association is now frequently considered at the haplotypic level. We suggest that there are difficulties in replicating association findings at the single-nucleotide-polymorphism (SNP) or the haplotype level, and we propose a shift toward a gene-based approach in which all common variation within a candidate gene is considered jointly. Inconsistencies arising from population differences are more readily resolved by use of a gene-based approach rather than either a SNP-based or a haplotype-based approach. A gene-based approach captures all of the potential risk-conferring variations; thus, negative findings are subject only to the issue of power. In addition, chance findings due to multiple testing can be readily accounted for by use of a genewide-significance level. Meta-analysis procedures can be formalized for gene-based methods through the combination of P values. It is only a matter of time before all variation within genes is mapped, at which point the gene-based approach will become the natural end point for association analysis and will inform our search for functional variants relevant to disease etiology.

Alleles↗
PubMedDate not supplied

Antibody response to Newcastle disease virus given by two different routes as measured by ELISA and hemagglutination-inhibition test and associated tracheal immunity.

The enzyme-linked immunosorbent assay (ELISA) and the conventional hemagglutination-inhibition (HI) test were compared for their ability to measure the primary serological response of chickens inoculated by the intranasal-intraocular (IN-IO) routes with Newcastle disease virus (NDV) and the secondary response after intratracheal (IT) challenge. In addition, these responses were compared with the temporal antibody response of chickens inoculated only once by the IT route. Both tests detected NDV-specific antibody by 7 days postinoculation (PI) in the IN-IO-inoculated group, while ELISA and the HI test detected antibody at 4 and 7 days, respectively, in the IT-inoculated group. Titers measured by each test were parallel in quantifying the antibody response, and titers rose anamnestically in response to secondary IT challenge at 21 days PI. ELISA titers remained high at 42 days PI, but the HI titers began to decline at this time. There was a good agreement (R = 0.94) between the results of the two tests throughout both primary and secondary responses. Conversely, there was little agreement between the results of the two tests after 21 days PI in the absence of secondary challenge. Antibody levels were higher when inoculation was by the primary IT route, and they persisted throughout the experiment (86 days). Ciliary activity served as a measure of tracheal immunity or infection of tracheal epithelium. It was reduced as early as 2 days PI and was nearly or completely absent by 5-6 days PI.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Intranasal↗
PubMed2006

Implicit cocaine associations in active cocaine users and controls.

Implicit and explicit cocaine-related cognitions were assessed in a sample of 16 cocaine-dependent poly-substance abusers and 16 age, gender, and SES-matched controls. Implicit associations were assessed with four unipolar versions of the Implicit Association Test (IAT), assessing associations between cocaine and positive affect, negative affect, arousal and sedation, relative to the contrast category "sports". Explicit cognitions were assessed with a questionnaire using the same words as the IAT. As expected, cocaine users scored higher on explicit arousal and lower on explicit sedation expectancies than controls. Unexpectedly, cocaine users demonstrated strong associations between cocaine and sedation and between cocaine and positive valence (relative to sports). Both associations were not found in controls. It is discussed that these paradoxical findings could be related to properties of the IATs used or that they may reflect a similar quieting effect as demonstrated for stimulants in children with ADHD.

Adult↗
PubMed1996

Cranial attachment of the gubernaculum associated with undescended testes.

Elongated epididymis is an abnormality encountered most frequently in patients who have an undescended testis (or testes). To clarify the implication of this anomaly in testicular descent, the anatomic configuration of paratesticular structures, especially the site of cranial attachment of the gubernaculum in relation to the configuration of the vas deferens, was evaluated in 54 undescended testes of 44 patients. Undescended testes were associated with an elongated epididymis in 42.5% of cases. Of these, the cranial gubernaculum was attached solely to the vas deferens in 73.9%. In this group, the cranial gubernaculum was attached to the most descended part of the loop of the vas deferens. No patient with a nonelongated epididymis had a gubernaculum attached solely to the vas deferens. These results suggest that the abnormal attachment of the cranial gubernaculum in the embryological stage might affect the mode of descent of adjacent paratesticular structures.

Child↗
PubMed2003

Event-related potentials and neuropsychological tests in obsessive-compulsive disorder.

OBJECTIVE: Previous studies have provided evidence from event-related potentials (ERPs) and neuropsychological testing of abnormal cognitive processing in obsessive-compulsive disorder (OCD). The aim of this study was to further characterize the cognitive functions of the patients with OCD by utilizing ERPs and neuropsychological tests. METHODS: ERPs were recorded in a group of 31 drug-free OCD patients without depression and 30 normal controls following verbal auditory stimuli using an oddball paradigm. The specific neuropsychological tests administered to assess cognitive functions in all participants were the Stroop Test, Trail Making Test, Design Fluency Test, Controlled Word Association Test (Verbal Fluency test). RESULTS: The patient group showed shorter P300 duration compared to normal controls. In neuropsychological tests, no significant differences were found between the two groups. Negative correlations between Stroop duration and P300 amplitudes in occipital, parietal, and temporal anterior regions were observed. CONCLUSION: Shorter P300 duration may indicate an acceleration in the P300 process, and speeding of cognitive processing, dysfunction of cortico-subcortical circuits, or some combination of all of the above.

Adolescent↗