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PubMed1988

Positive Coombs' test associated with ulcerative colitis. A prevalence study.

Among 112 patients with ulcerative colitis (UC), a positive Coombs' test was detected in two cases. The immunoglobulins were IgG and no complement could be detected on the red cells. None of the two patients showed laboratory evidence of hemolysis, although reduced red cell survival was suspected in one patient with a 6-year history of UC, previous autoimmune hemolytic anemia and a positive in vitro monocyte-macrophage phagocytosis test. The HLA-antigens in the two patients were different except for the common antigen HLA-A1.

Adolescent↗
PubMed2002

Association tests with systemic lupus erythematosus (SLE) of IL10 markers indicate a direct involvement of a CA repeat in the 5' regulatory region.

Many lines of evidence suggest that IL10 is a strong candidate gene for systemic lupus erythematosus (SLE) susceptibility. In our previously reported study an allele (IL10.G-140bp) of the microsatellite IL10.G located at position -1100 was significantly increased in Italian SLE patients in comparison with controls. Starting from this observation, we tested if sequence variations in the vicinity of IL10.G were more strongly associated with SLE. We performed a comprehensive association study including 26 SNPs (of which four were newly identified in the present study by DHPLC analysis) spanning 8.5 Kb of the 5' flanking and the transcribed region of the IL10 gene. The association study was performed by the DNA pool method on an extended panel of Italian patients (205) and controls (631). Haplotypic associations were studied by individual typing of seven selected markers surrounding IL10.G. Gene, genotype and haplotype frequencies were not significantly different in patients and controls. Thus the IL10.G microsatellite remains to date the only IL10 marker associated with SLE in our population. A meta-analysis of all published results indicates a possible direct role of the IL10.G repeat number in SLE susceptibility.

5' Flanking Region↗
PubMed2006

Family-based association test for time-to-onset data with time-dependent differences between the hazard functions.

In genetic association studies, the differences between the hazard functions for the individual genotypes are often time-dependent. We address the non-proportional hazards data by using the weighted logrank approach by Fleming and Harrington [1981]:Commun Stat-Theor M 10:763-794. We introduce a weighted FBAT-Logrank whose weights are based on a non-parametric estimator for the genetic marker distribution function under the alternative hypothesis. We show that the computation of the marker distribution under the alternative does not bias the significance level of any subsequently computed FBAT-statistic. Hence, we use the estimated marker distribution to select the Fleming-Harrington weights so that the power of the weighted FBAT-Logrank test is maximized. In simulation studies and applications to an asthma study, we illustrate the practical relevance of the new methodology. In addition to power increases of 100% over the original FBAT-Logrank test, we also gain insight into the age at which a genotype exerts the greatest influence on disease risk.

Age of Onset↗
PubMed1981

Hemostatic function tests associated with diabetic microangiopathy.

To study the possible role of an increased thrombotic tendency in the vascular complications of diabetes, several tests of hemostatic function were carried out on 91 men and 63 women aged 35-54 years with diabetes and the results compared with findings of 683 men and 393 women of the same age in the Northwick Park Heart Study. Mean values for factor VII, fibrinogen, antithrombin III and platelet adhesiveness were higher in the diabetics, but mean fibrinolytic activity was lower, particularly in the noninsulin-dependent group. Diabetics with retinopathy had higher factor VII and antithrombin III values, and those with proteinuria had higher values for factor VII, fibrinogen and platelet adhesiveness than those without these complications. These findings suggest a potentially important association between a thrombotic tendency and microangiopathy in diabetics, but prospective studies are needed to clarify whether the association is a casual one.

Adult↗
PubMed2006

Neural tube defects and folate pathway genes: family-based association tests of gene-gene and gene-environment interactions.

BACKGROUND: Folate metabolism pathway genes have been examined for association with neural tube defects (NTDs) because folic acid supplementation reduces the risk of this debilitating birth defect. Most studies addressed these genes individually, often with different populations providing conflicting results. OBJECTIVES: Our study evaluates several folate pathway genes for association with human NTDs, incorporating an environmental cofactor: maternal folate supplementation. METHODS: In 304 Caucasian American NTD families with myelomeningocele or anencephaly, we examined 28 polymorphisms in 11 genes: folate receptor 1, folate receptor 2, solute carrier family 19 member 1, transcobalamin II, methylenetetrahydrofolate dehydrogenase 1, serine hydroxymethyl-transferase 1, 5,10-methylenetetrahydrofolate reductase (MTHFR), 5-methyltetrahydrofolate-homo-cysteine methyltransferase, 5-methyltetrahydrofolate-homocysteine methyltransferase reductase, betaine-homocysteine methyltransferase (BHMT), and cystathionine-beta-synthase. RESULTS: Only single nucleotide polymorphisms (SNPs) in BHMT were significantly associated in the overall data set; this significance was strongest when mothers took folate-containing nutritional supplements before conception. The BHMT SNP rs3733890 was more significant when the data were stratified by preferential transmission of the MTHFR rs1801133 thermolabile T allele from parent to offspring. Other SNPs in folate pathway genes were marginally significant in some analyses when stratified by maternal supplementation, MTHFR, or BHMT allele transmission. CONCLUSIONS: BHMT rs3733890 is significantly associated in our data set, whereas MTHFR rs1801133 is not a major risk factor. Further investigation of folate and methionine cycle genes will require extensive SNP genotyping and/or resequencing to identify novel variants, inclusion of environmental factors, and investigation of gene-gene interactions in large data sets.

Alleles↗
PubMed1997

[False positive FDP test associated with malignant lymphoma].

We present a man with non-Hodgkin's lymphoma who had false positive FDP test results and who had monoclonal IgM and IgG. At admission, laboratory examinations showed elevated FDP levels and prolonged PT and APTT, which did not improve by anti-coagulation therapy. Although coagulation system data returned to normal levels after steroid pulse therapy, the FDP level increased. Positive pregnancy test and results of dilution analyses on FDP assay yielded a diagnosis of false positive FDP test results due to serum latex agglutinin. The addition of anti-immunoglobulin antibody inhibited latex agglutination by serum. FDP levels positively correlated with serum IgM concentrations. These data suggest that the false positive FDP test in this case was due to latex agglutination by monoclonal IgM.

Connectin↗
PubMed1985

Positive direct antiglobulin test associated with hyperglobulinemia in acquired immunodeficiency syndrome (AIDS).

This study determined the prevalence and clinical significance of a positive direct antiglobulin test (DAT) observed in pretransfusion tests on red cells from patients with acquired immunodeficiency syndrome (AIDS). Transfusion service records showed that prevalence of a positive DAT on red cells was 18% (10/55) in AIDS patients compared to 0.6% in general hospital patients during a 2-year period (1981-1983). A similar rate of 18% (8/45) was observed in other hyperglobulinemic patients. Of the 10 AIDS patients whose red cells were DAT positive, four had IgG and complement, four had IgG, and two had complement alone on their red cells. The eluates were not reactive with normal red cells nor with penicillin or cephalothin-coated red cells. Clinically, no hemolysis was observed. In this series a positive DAT in AIDS patients appeared not to be associated with autoimmune hemolytic anemia. The positive DAT in AIDS patients may be due to the hyperglobulinemic state.

Acquired Immunodeficiency Syndrome↗
PubMed2002

Sensitivity of three urinary antigen tests associated with clinical severity in a large outbreak of Legionnaires' disease in The Netherlands.

In 1999 an outbreak involving 188 patients with Legionnaires' disease (LD) occurred among visitors to a flower show in the Netherlands. Two enzyme immunoassays (Binax and Biotest) and one immunochromatographic assay (Binax NOW) were tested, using urine samples from LD patients from the 1999 outbreak. Sensitivity was calculated using positive culture and/or seroconversion as the "gold standard" in outbreak-related patients with radiographically confirmed pneumonia who fulfilled the epidemiological critera. The Binax EIA, Biotest EIA, and Binax NOW assay showed overall sensitivities of 69, 71, and 72%, respectively. When the tests were performed with concentrated urine samples, the overall sensitivities increased to 79, 74, and 81%, respectively. Using multiple logistic regression analysis with backward elimination, a statistically significant association was found between clinical severity and test sensitivity for all tests. For patients with mild LD, the test sensitivities ranged from 40 to 53%, whereas for patients with severe LD who needed immediate special medical care, the sensitivities reached 88 to 100%. These findings have major implications for the diagnostic process in patients with mild pneumonia and suggest that patients with mild pneumonia may go underdiagnosed if urine antigen tests alone are used.

Aged↗
PubMed2005

Tests of association between quantitative traits and haplotypes in a reduced-dimensional space.

Candidate gene association tests are currently performed using several intragenic SNPs simultaneously, by testing SNP haplotype or genotype effects in multifactorial diseases or traits. The number of haplotypes drastically increases with an increase in the number of typed SNPs. As a result, large numbers of haplotypes will introduce large degrees of freedom in haplotype-based tests, and thus limit the power of the tests. In this study we propose using the principal component method to reduce the dimension, and then construct association tests on the lower-dimensional space to test the association between haplotypes and a quantitative trait using population-based samples. The proposed method allows ambiguous haplotypes. We use simulation studies to evaluate the type I error rate of the tests, and compare the power of the proposed tests with that of the tests without dimension reduction, and the tests with dimension reduction by merging rare haplotypes. The simulation results show that the proposed tests have correct type I error rates and are more powerful than other tests in most cases considered in our simulation studies.

Computer Simulation↗
PubMed1994

Norms for depressed patients for the California verbal learning test: associations with depression severity and self-report of cognitive difficulties.

This study provides norms for depressed subjects for a widely used test of verbal memory, the California Verbal Learning Test (CVLT). Subjects were 156 outpatients with major depression tested during a drug washout period. Mean CVLT memory scores for these patients were generally between one-half and one standard deviation below age- and sex-corrected norms for nondepressed populations. Severity of depression in the patients was not associated with memory performance, but was associated with self-report of cognitive difficulties. A table of age-, sex-, and education-specific norms for the CVLT is provided.

Journal Article↗
PubMed1997

Evaluation of recommendations for replication-competent retrovirus testing associated with use of retroviral vectors.

With input from the gene therapy community, CBER is actively examining the recommendations for RCR testing during retroviral vector production, production of ex vivo-transduced cells, and in patients who receive such material. Our initial recommendations were made at a time when our experience with RCR detection assays and clinical use of retroviral vectors was limited. As the gene therapy field has matured, there is an increasing amount of data available on RCR detection assays and from monitoring of patients in clinical trials. The cumulative data give assurance that RCR detection assays in use are of sufficient sensitivity to provide a margin of safety to patients: no patients to date have evidence of RCR infection. However, CBER encourages members of the gene therapy community to continue to submit data to the FDA or to publish data that will enhance the cumulative data base on RCR testing assays, experience with different VPC, and patient monitoring. Based on the analysis of data accumulated to data, and ongoing discussions with members of the gene therapy community, CBER is proposing to discuss changes to the current RCR testing recommendations, as summarized below. RCR testing during production of retroviral vector and ex vivo-transduced cells. Development of characterized standards for RCR testing of supernatant and cells should allow comparison of assay sensitivity. One proposal under consideration is to apply statistical methods to determine how much material needs to be tested independent of the size of the production lot. Data and discussion are still needed to define a limit concentration and a value for probability of detection for RCR testing, while maintaining an appropriate margin of safety. These modifications of RCR testing strategies could lead to improvements in assay sensitivity. Additional discussion and data are also needed to evaluate the current recommendations of the testing for ex vivo-transduced cells: should both cells and supernatant be tested in all cases? RCR testing during patient follow-up. The time points required for RCR testing during patient follow-up need examination. One proposal under consideration is to sample and assay at three time points during the first year of treatment (e.g., 4-6 weeks, 3 months, and 1 year post-treatment). Further discussion is needed to define appropriate additional follow-up. Choice of assays to detect surrogate markers for RCR infection (i.e., serologic or PCR-based assays) should consider mode of vector administration and the patient population. Positive results with such assays should be pursued by direct culture assay to obtain and characterize the infectious viral isolate. These proposals will be the focal point for the discussion at the Retroviral Vector Breakout Session at the 1997 FDA/NIH Gene Therapy Conference. After the 1997 FDA/NIH Gene Therapy Conference, CBR plans to propose revised recommendations for RCR testing for public comment.

Cell Transformation, Viral↗
PubMed2006

Failure to find an association between CD14-159C/T polymorphism and asthma: a family-based association test and meta-analysis.

BACKGROUND: CD14 is an essential component of the receptor for lipopolysaccharide (LPS). LPS stimulates T-helper type 1 (Th1) cytokine expression, potentially suppressing Th2 immune responses involved in IgE-mediated allergic diseases. Previous studies have reported that -159C/T, a promoter polymorphism of CD14, is associated with total serum IgE levels and atopy, but other studies have shown conflicting results. METHODS: To examine possible associations of CD14 polymorphisms with asthma susceptibility, we performed transmission disequilibrium tests (TDTs) of 137 Japanese families identified through children with atopic asthma. RESULTS: We found no association between -159C/T polymorphism and asthma (p= 0.37). Quantitative TDT and ANOVA showed no association between the -159C/T genotype and total serum IgE levels. We also performed a meta-analysis of data from all available studies. Neither a fixed-effects model nor a random-effect model showed a significant odds ratio for the -159C/T polymorphism (p > 0.1). CONCLUSIONS: Our data indicate that CD14 does not contribute substantially to susceptibility to asthma. Further studies examining both genotypes and environmental factors will be necessary to elucidate the role of CD14 in the development of allergic diseases.

Asthma↗
PubMed1985

Positive direct antiglobulin test associated with echinococcosis: a case report.

A patient with hydatid cyst of the liver was found to have a positive direct antiglobulin test, with IgG and complement on his red blood cells (RBCs), but with no evidence of haemolysis. The positive direct antiglobulin test disappeared following surgical removal of the cyst. To the best of our knowledge no such case has been reported in the literature.

Adult↗
PubMed2002

Power and sample size calculations for case-control genetic association tests when errors are present: application to single nucleotide polymorphisms.

The purpose of this work is to quantify the effects that errors in genotyping have on power and the sample size necessary to maintain constant asymptotic Type I and Type II error rates (SSN) for case-control genetic association studies between a disease phenotype and a di-allelic marker locus, for example a single nucleotide polymorphism (SNP) locus. We consider the effects of three published models of genotyping errors on the chi-square test for independence in the 2 x 3 table. After specifying genotype frequencies for the marker locus conditional on disease status and error model in both a genetic model-based and a genetic model-free framework, we compute the asymptotic power to detect association through specification of the test's non-centrality parameter. This parameter determines the functional dependence of SSN on the genotyping error rates. Additionally, we study the dependence of SSN on linkage disequilibrium (LD), marker allele frequencies, and genotyping error rates for a dominant disease model. Increased genotyping error rate requires a larger SSN. Every 1% increase in sum of genotyping error rates requires that both case and control SSN be increased by 2-8%, with the extent of increase dependent upon the error model. For the dominant disease model, SSN is a nonlinear function of LD and genotyping error rate, with greater SSN for lower LD and higher genotyping error rate. The combination of lower LD and higher genotyping error rates requires a larger SSN than the sum of the SSN for the lower LD and for the higher genotyping error rate.

Case-Control Studies↗
PubMed2004

Rate-dependent QRS prolongation during exercise testing associated with hyperkalemia.

The present case showed gradual increase of QRS duration from 100 ms up to 180 msec during an ergometer exercise test along with the heart rate increase. After exercise, QRS duration shortened and normalized. Laboratory test showed hyperkalemia (K = 8.0 mEq/l). T1 myocardial scintigraphy revealed exercise-induced transient ischemia in posterolateral region of left ventricle. Coronary angiography showed significant stenosis in the distal portion of left circumflex coronary artery. The increase of QRS duration was possibly due to the combination of hyperkalemia and the effect of mexiletine. The rate dependent blocking effect on sodium channel of mexiletine might be intensified under hyperkalemia.

Aged↗
PubMed2005

Association testing of variants in the hepatocyte nuclear factor 4alpha gene with risk of type 2 diabetes in 7,883 people.

Two recent publications reported association of common polymorphisms in the P2 promoter of hepatocyte nuclear factor 4alpha (HNF4alpha) (the MODY1 gene) with risk for type 2 diabetes. We attempted to reproduce this putative association by genotyping 11 single nucleotide polymorphism (SNPs) spanning the HNF4alpha coding region and the P2 promoter in >3,400 patients and control subjects from Sweden, Finland, and Canada. One SNP that was consistently associated in the two previous reports (rs1884613, in the P2 promoter region) also trended in the same direction in our sample, albeit with a lower estimated odds ratio (OR) of 1.11 (P = 0.05, one-tailed). We genotyped this SNP (rs1884613) in an additional 4,400 subjects from North America and Poland. In this sample, the association was not confirmed and trended in the opposite direction (OR 0.88). Meta-analysis of our combined sample of 7,883 people (three times larger than the two initial reports combined) yielded an OR of 0.97 (P = 0.27). Finally, we provide an updated analysis of haplotype structure in the region to guide any further investigation of common variation in HNF4alpha. Although our combined results fail to replicate the previously reported association of common variants in HNF4alpha with risk for type 2 diabetes, we cannot exclude an effect smaller than that originally proposed, heterogeneity among samples, variation in as-yet-unmeasured genotypic or environmental modifiers, or true association secondary to linkage disequilibrium (LD) with as-yet-undiscovered variant(s) in the region.

Adult↗
PubMed2004

Is cervical spine rotation, as used in the standard vertebrobasilar insufficiency test, associated with a measureable change in intracranial vertebral artery blood flow?

Cervical spine rotation is used by manual therapists as a premanipulative vertebrobasilar insufficiency (VBI) test to identify patients at risk of developing VBI post-manipulation. Investigations of the effect of rotation on vertebral artery blood flow have yielded conflicting results, the validity of the test being debated. It was the aim of this study, therefore, to investigate the effects of cervical spine rotation on vertebral artery blood flow. Transcranial Doppler sonography was used to measure intracranial vertebral artery blood flow in 30 young, healthy, female subjects, with the cervical spine in the neutral position and with sustained, end-of-range rotation. Statistically significant decreases in blood flow were demonstrated with contralateral rotation particularly, in the left (45.9+/-8.5 to 41.8+/-11.6 cm/s) and right (27.8+/-6.9 to 25.2+/-8.2 cm/s) vertebral arteries. Despite this change in blood flow, signs and symptoms of VBI were not demonstrated in these subjects. Nevertheless, these findings are of clinical importance, especially in patients who may have underlying vascular pathology. Thus, this study supports the use of the VBI test, in the absence of a more specific, sensitive and valid test, to assess the adequacy of hindbrain blood supply to identify those patients who may be at risk of serious complications post-manipulation.

Adult↗
PubMed2005

Multifactor-dimensionality reduction versus family-based association tests in detecting susceptibility loci in discordant sib-pair studies.

Complex diseases are generally thought to be under the influence of multiple, and possibly interacting, genes. Many association methods have been developed to identify susceptibility genes assuming a single-gene disease model, referred to as single-locus methods. Multilocus methods consider joint effects of multiple genes and environmental factors. One commonly used method for family-based association analysis is implemented in FBAT. The multifactor-dimensionality reduction method (MDR) is a multilocus method, which identifies multiple genetic loci associated with the occurrence of complex disease. Many studies of late onset complex diseases employ a discordant sib pairs design. We compared the FBAT and MDR in their ability to detect susceptibility loci using a discordant sib-pair dataset generated from the simulated data made available to participants in the Genetic Analysis Workshop 14. Using FBAT, we were able to identify the effect of one susceptibility locus. However, the finding was not statistically significant. We were not able to detect any of the interactions using this method. This is probably because the FBAT test is designed to find loci with major effects, not interactions. Using MDR, the best result we obtained identified two interactions. However, neither of these reached a level of statistical significance. This is mainly due to the heterogeneity of the disease trait and noise in the data.

Chromosome Mapping↗