PubMed Health⌕ Search

Biomedical subjects

E R Bleecker

Publications and source records attributed to E R Bleecker.

At least 19 recordsLinked to original sources
PubMed2006

Overview of the pharmacogenetics of asthma treatment.

Asthma affects approximately 300 million individuals worldwide. Medications comprise a substantial portion of asthma expenditures. Despite the availability of three primary therapeutic classes of medications, there are a significant number of nonresponders to therapy. Available data, as well as previous pharmacogenetic studies, suggest that genetics may contribute as much as 60-80% to the interindividual variability in treatment response. In this methodologic review, after providing a broad overview of the asthma pharmacogenetics literature to date, we describe the application of a novel family-based screening algorithm to the analysis of pharmacogenetic data and highlight our approach to identifying and verifying loci influencing asthma treatment response. This approach seeks to address issues related to multiple comparisons, statistical power, population stratification, and failure to replicate from which previous population-based or case-control pharmacogenetic association studies may suffer. Identification of such replicable loci is the next step towards the goal of 'individualized therapy' for asthma.

Adrenergic beta-Agonists↗
PubMed2004

Genome scan for loci linked to mite sensitivity: the Collaborative Study on the Genetics of Asthma (CSGA).

Mite sensitivity has been reported to be a major risk factor for asthma. As part of the Collaborative Study on the Genetics of Asthma (CSGA), a genome scan using mite reactivity (Dermatophagoides Pteronyssinus (Der p) and Dermatophagoides farinae (Der f)) as the phenotype was conducted. In 287 CSGA families, 122 were informative for linkage. Evidence supporting linkage was observed for regions on chromosome 19 (D19S591, lod=2.43, P=0.0008; D19S1037, lod=1.57, P=0.007) and chromosome 20 (D20S473/D20S604, lod=1.41, P=0.01). All three ethnic groups appeared to contribute to the evidence for linkage on chromosome 20. African-American families gave strongest support for linkage on chromosomes 3 (D3S2409, lod=1.33, P=0.01), 12 (D12S373, lod=1.51, P=0.008) and 18 (ATA82B02, lod=1.32, P=0.01). Caucasian families showed strong evidence for linkage on chromosome 19 (D19S591, lod=3.51, P=0.00006). Hispanic families supported linkage on chromosomes 11 (D11S1984, lod=1.56, P=0.007), 13 (D13S787, lod=1.30, P=0.01) and 20 (D20S470, lod=1.71, P=0.005). These results suggest that multiple genes may be involved in controlling skin reactivity to Dermatophoigoies.

Animals↗
PubMed2004

Polymorphisms of the ADAM33 gene are associated with accelerated lung function decline in asthma.

BACKGROUND: Asthma is a genetically complex disease characterized by respiratory symptoms, intermittent airway obstruction and airway hyper-responsiveness due to airway inflammation and remodelling. The ADAM33 gene is associated with asthma and airway hyper-responsiveness and is postulated as a gene for airway remodelling. OBJECTIVE: To investigate whether polymorphisms of the ADAM33 gene are associated with accelerated lung function decline in patients with asthma. METHODS: In a cohort of 200 asthma patients followed over 20 years, eight single nucleotide polymorphisms of the ADAM33 gene were analysed to estimate their effect on annual FEV(1) decline. RESULTS: The rare allele of the S_2 polymorphism was significantly associated with excess decline in FEV(1) (P<0.05). CONCLUSION: These findings suggest that a variant in ADAM33 is not only important in the development of asthma but also in disease progression, possibly related to enhanced airway remodelling.

ADAM Proteins↗
PubMed2003

Polymorphisms in the CYP1B1 gene are associated with increased risk of prostate cancer.

CYP1B1 has been evaluated as a candidate gene for various cancers because of its function in activating environmental procarcinogens and catalysing the conversion of oestrogens to genotoxic catechol oestrogens. To test the hypothesis that genetic polymorphisms in the CYP1B1 gene may associate with the risk for prostate cancer (CaP), we compared the allele, genotype, and haplotype frequencies of 13 single nucleotide polymorphisms (SNPs) of CYP1B1 among 159 hereditary prostate cancer (HPC) probands, 245 sporadic CaP cases, and 222 unaffected men. When each of the SNPs was analysed separately, marginally significant differences were observed for allele frequencies between sporadic cases and controls for three consecutive SNPs (-1001C/T, -263G/A, and -13C/T, P=0.04-0.07). Similarly, marginally significant differences between sporadic cases and controls in the frequency of variant allele carriers were observed for five consecutive SNPs (-1001C/T, -263G/A, -13C/T, +142C/G, and +355G/T, P=0.02-0.08). Interestingly, when the combination of these five SNPs was analysed using a haplotype approach, a larger difference was found (P=0.009). One frequent haplotype (C-G-C-C-G of -1001C/T, -263G/A, -13C/T, +142C/G, and +355G/T) was associated with an increased risk for CaP, while the other frequent haplotype (T-A-T-G-T) was associated with a decreased risk for CaP. These findings suggest that genetic polymorphisms in CYP1B1 may modify the risk for CaP.

Aryl Hydrocarbon Hydroxylases↗
PubMed2003

Sibling effect on atopy in children of patients with asthma.

BACKGROUND: Multiple population studies have shown the presence of a sibling effect on atopic disease. However, it is unclear if the sibling effect is also of importance in subjects who are genetically at high risk for the development of atopy. OBJECTIVE: To study the presence of a sibling effect on markers of atopy (serum total IgE, specific IgE, skin tests) and asthma (bronchial hyper-responsiveness to histamine) in families ascertained through a parent with asthma. METHODS: First-degree offspring in 200 asthma families were studied (n = 541). Mixed effects regression models were used to account for the dependence of the observations within a family, and to adjust for possible confounding variables. RESULTS: Multiple regression analysis showed that having older siblings was inversely related to atopy, defined as >/= 2, >/= 3, >/= 4, or >/= 5 skin tests (P = 0.07-0.009). In addition, family size (number of siblings) had a significant protective effect on the presence of specific IgE to common aeroallergens (P = 0.03). Exposure to cigarette smoke in the first 3 years of life significantly increased the risk of having specific IgE to common aeroallergens (P = 0.04). No sibling effect was detected for serum total IgE or bronchial hyper-responsiveness to histamine. CONCLUSIONS: This study shows a protective sibling effect on the presence and severity of atopy but not on bronchial hyper-responsiveness in children who are genetically at risk. The identification of the sibling effect in high-risk families stresses the need to understand the basis of this effect, in order to design future prevention programmes.

Adolescent↗
PubMed2003

Risk factors associated with the presence of irreversible airflow limitation and reduced transfer coefficient in patients with asthma after 26 years of follow up.

BACKGROUND: Childhood asthma is generally believed to be a disorder with a good prognosis. However, some asthmatics develop irreversible airway obstruction, probably as a result of airway remodelling. METHODS: After 21-33 years, 228 adults (aged 13-44 years at baseline) with a history of asthma were re-examined to assess risk factors for the development of irreversible airway obstruction (IAO, forced expiratory volume in 1 second (FEV(1)) <80% predicted and reversibility <9% predicted) and a reduced postbronchodilator transfer coefficient (carbon monoxide transfer factor/alveolar volume, <80% predicted), both characteristics of COPD. RESULTS: At follow up, 41% did not have airway obstruction (NAO), 43% had reversible airway obstruction (RAO), and 16% had IAO; 23% had a reduced transfer coefficient. Patients with RAO had asthma-like characteristics (wheezing, asthma attacks, bronchial hyperresponsiveness (BHR)) while patients with IAO had COPD-like symptoms (cough, phlegm, dyspnoea) at follow up. The development of IAO is determined by a lower FEV(1), less reversibility of airway obstruction and, surprisingly, less severe BHR at initial screening. Eighty percent of the patients with asthma who used anti-inflammatory medication still had airway obstruction, but IAO developed less frequently. Smoking was associated with a reduced transfer coefficient but not with the development of IAO. Female sex was associated with a reduced transfer coefficient, whereas corticosteroid use was not. CONCLUSIONS: Although IAO and a low transfer coefficient are both characteristics of COPD, they represent distinct entities in adult asthmatics in terms of symptomatology, aetiology, and probably in therapeutic approaches and disease prevention.

Adolescent↗
PubMed2001

Linkage and association of CYP17 gene in hereditary and sporadic prostate cancer.

Androgens are essential for prostate development, growth and maintenance and the association between androgen levels and prostate cancer is well established. Since the CYP17 gene encodes the enzyme cytochrome P450c17alpha, which mediates 17alpha-hydroxylase and 17,20-lyase activities in the androgen biosynthesis pathway, sequence variations in the gene and association with increased risk to prostate cancer has been studied. In particular, several groups have studied the association between a polymorphism in the 5' promoter region and prostate cancer using a population-based association approach. However, the results from these studies were inconclusive. To further study this polymorphism and its possible role in hereditary prostate cancer (HPC), we performed a genetic linkage analysis and family-based association analysis in 159 families, each of which contains at least 3 first-degree relatives with prostate cancer. In addition, we performed a population-based association analysis to compare the risk of this polymorphism to hereditary and sporadic prostate cancer in 159 HPC probands, 249 sporadic prostate cancer patients and 211 unaffected control subjects. Evidence for linkage at the CYP17 gene region was found in the total 159 HPC families (LOD = 1.3, p = 0.01, at marker D10S222). However, family-based association tests did not provide evidence for overtransmission of either allele of the CYP17 polymorphism to affected individuals in the HPC families. The allele and genotype frequencies of the polymorphism were not statistically different among the HPC probands, sporadic cases and unaffected control subjects. In conclusion, our results suggest that the CYP17 gene or other genes in the region may increase the susceptibility to prostate cancer in men; however, the polymorphism in the 5' promoter region has a minor role if any in increasing prostate cancer susceptibility in our study sample.

Adult↗
PubMed2001

A comparison of short-term treatment with inhaled fluticasone propionate and zafirlukast for patients with persistent asthma.

PURPOSE: To compare the short-term efficacy and safety of low-dose fluticasone propionate with that of oral zafirlukast therapy for patients previously treated with beta-2-agonists alone, and to evaluate the potential therapeutic benefit of switching from zafirlukast to a low-dose inhaled corticosteroid. SUBJECTS AND METHODS: This study consisted of a 4-week randomized, double-blind treatment period followed by a 4-week open-label period. Two hundred ninety-four patients > or =12 years old with asthma previously uncontrolled with beta-2-agonists alone were randomly assigned to treatment with low-dose inhaled fluticasone (88 microg twice daily) or oral zafirlukast (20 mg twice daily). After 4 weeks, all patients discontinued their double-blind therapy and received open-label fluticasone (88 microg twice daily). Outcomes included pulmonary function, asthma symptoms, albuterol use, asthma exacerbations, and adverse events. RESULTS: During the double-blind treatment period, fluticasone patients had significantly greater improvements in morning peak flow (29.3 L/min vs. 18.3 L/min), percentage of symptom-free days (19.8% vs. 11.6%), and daily albuterol use (-1.8 puffs per day vs. -1.1 puffs per day) compared with zafirlukast patients (P < or =0.025, each comparison). During the open-label treatment period, patients switched from zafirlukast to fluticasone experienced additional improvements in morning peak flow (17.2 L/min), evening peak flow (13.6 L/min), and FEV(1) (0.11 liter) and daily albuterol use (-0.9 puffs daily) compared with values obtained at the end of the double-blind treatment period (P < or =0.001, each comparison). CONCLUSION: Low-dose fluticasone was more effective than zafirlukast in improving pulmonary function and symptoms in patients with persistent asthma. In addition, switching patients from zafirlukast to fluticasone further improved clinical outcomes.

Administration, Inhalation↗
PubMed2001

Linkage and association studies of prostate cancer susceptibility: evidence for linkage at 8p22-23.

Multiple lines of evidence have implicated the short arm of chromosome 8 as harboring genes important in prostate carcinogenesis. Although most of this evidence comes from the identification of frequent somatic alterations of 8p loci in prostate cancer cells (e.g., loss of heterozygosity), studies have also suggested a role for 8p genes in mediation of inherited susceptibility to prostate cancer. To further examine this latter possibility, we performed linkage analyses, in 159 pedigrees affected by hereditary prostate cancer (HPC), using 24 markers on the short arm of chromosome 8. In the complete set of families, evidence for prostate cancer linkage was found at 8p22-23, with a peak HLOD of 1.84 (P=.004), and an estimate of the proportion of families linked (alpha) of 0.14, at D8S1130. In the 79 families with average age at diagnosis >65 years, an allele-sharing LOD score of 2.64 (P=.0005) was observed, and six markers spanning a distance of 10 cM had LOD scores >2.0. Interestingly, the small number of Ashkenazi Jewish pedigrees (n=11) analyzed in this study contributed disproportionately to this linkage. Mutation screening in HPC probands and association analyses in case subjects (a group that includes HPC probands and unrelated case subjects) and unaffected control subjects were carried out for the putative prostate cancer-susceptibility gene, PG1, previously localized to the 8p22-23 region. No statistical differences in the allele, genotype, or haplotype frequencies of the SNPs or other sequence variants in the PG1 gene were observed between case and control subjects. However, case subjects demonstrated a trend toward higher homozygous rates of less-frequent alleles in all three PG1 SNPs, and overtransmission of a PG1 variant to case subjects was observed. In summary, these results provide evidence for the existence of a prostate cancer-susceptibility gene at 8p22-23. Evaluation of the PG1 gene and other candidate genes in this area appears warranted.

Age of Onset↗
PubMed2001

Genomewide screen and identification of gene-gene interactions for asthma-susceptibility loci in three U.S. populations: collaborative study on the genetics of asthma.

The genomewide screen to search for asthma-susceptibility loci, in the Collaborative Study on the Genetics of Asthma (CSGA), has been conducted in two stages and includes 266 families (199 nuclear and 67 extended pedigrees) from three U.S. populations: African American, European American, and Hispanic. Evidence for linkage with the asthma phenotype was observed for multiple chromosomal regions, through use of several analytical approaches that facilitated the identification of multiple disease loci. Ethnicity-specific analyses, which allowed for different frequencies of asthma-susceptibility genes in each ethnic population, provided the strongest evidence for linkage at 6p21 in the European American population, at 11q21 in the African American population, and at 1p32 in the Hispanic population. Both the conditional analysis and the affected-sib-pair two-locus analysis provided further evidence for linkage, at 5q31, 8p23, 12q22, and 15q13. Several of these regions have been observed in other genomewide screens and linkage or association studies, for asthma and related phenotypes. These results were used to develop a conceptual model to delineate asthma-susceptibility loci and their genetic interactions, which provides a promising basis for initiation of fine-mapping studies and, ultimately, for gene identification.

Adolescent↗
PubMed2001

Evaluation of linkage and association of HPC2/ELAC2 in patients with familial or sporadic prostate cancer.

To investigate the relationship between HPC2/ELAC2 and prostate cancer risk, we performed the following analyses: (1) a linkage study of six markers in and around the HPC2/ELAC2 gene at 17p11 in 159 pedigrees with hereditary prostate cancer (HPC); (2) a mutation-screening analysis of all coding exons of the gene in 93 probands with HPC; (3) family-based and population-based association study of common HPC2/ELAC2 missense variants in 159 probands with HPC, 249 patients with sporadic prostate cancer, and 222 unaffected male control subjects. No evidence for linkage was found in the total sample, nor in any subset of pedigrees based on characteristics that included age at onset, number of affected members, male-to-male disease transmission, or race. Furthermore, only the two previously reported missense changes (Ser217Leu and Ala541Thr) were identified by mutational analysis of all HPC2/ELAC exons in 93 probands with HPC. In association analyses, family-based tests did not reveal excess transmission of the Leu217 and/or Thr541 alleles to affected offspring, and population-based tests failed to reveal any statistically significant difference in the allele frequencies of the two polymorphisms between patients with prostate cancer and control subjects. The results of this study lead us to reject the three alternative hypotheses of (1) a highly penetrant, major prostate cancer-susceptibility gene at 17p11, (2) the allelic variants Leu217 or Thr541 of HPC2/ELAC2 as high-penetrance mutations, and (3) the variants Leu217 or Thr541 as low-penetrance, risk-modifying alleles. However, we did observe a trend of higher Leu217 homozygous carrier rates in patients than in control subjects. Considering the impact of genetic heterogeneity, phenocopies, and incomplete penetrance on the linkage and association studies of prostate cancer and on the power to detect linkage and association in our study sample, our results cannot rule out the possibility of a highly penetrant prostate cancer gene at this locus that only segregates in a small number of pedigrees. Nor can we rule out a prostate cancer-modifier gene that confers a lower-than-reported risk. Additional larger studies are needed to more fully evaluate the role of this gene in prostate cancer risk.

Age of Onset↗
PubMed2001

Evidence for a prostate cancer linkage to chromosome 20 in 159 hereditary prostate cancer families.

Prostate cancer is the most common malignancy diagnosed in men in the US. Genetic susceptibility to prostate cancer has been well documented. A region at chromosome 20q13 (HPC20) has been reported to be linked to a prostate cancer susceptibility gene. To confirm this finding, we genotyped 16 markers spanning approximately 95 cM on chromosome 20 in 159 hereditary prostate cancer (HPC) families. Positive (but not statistically significant) linkage scores were observed from 20pter to 20q11, with the highest non-parametric linkage (NPL) score for the complete dataset of 1.02 (P=0.15) being observed at D20S195 at 20q11. Evidence for linkage from parametric analyses with a dominant or a recessive model was weak. Interestingly, consistent with the original findings of linkage to 20 g higher linkage scores were observed in the subsets of families with a later age at diagnosis (> or =65 years; n=80, NPL=1.94, P=0.029 at D20S186), fewer than five affected family members (n=69, NPL=1.74, P=0.037 at D20S889), or without male-to-male disease transmission (n=60, NPL=1.01, P=0.15 at D20S117). The region with positive linkage scores spanned approximately 60 cM from 20pter to 20q11 in these subsets of families. Our results are consistent with a prostate cancer susceptibility locus on chromosome 20.

Aged↗
PubMed2001

Ethnic differences in asthma and associated phenotypes: collaborative study on the genetics of asthma.

BACKGROUND: In the Collaborative Study on the Genetics of Asthma, 314 families with 2584 subjects were characterized for asthma and allergy. OBJECTIVE: The purpose of this investigation was to examine clinical heterogeneity observed in asthma and allergic characteristics among 3 ethnic groups (African American, white, and Hispanic family members). METHODS: Pulmonary function parameters and asthma associated phenotypes were compared among the ethnic groups. RESULTS: In comparison with the other groups, African American sibling pairs had a significantly lower baseline FEV(1) percent of predicted (P =.0001) and a higher rate of skin test reactivity to cockroach allergen (P =.0001); Hispanic sibling pairs had significantly more skin reactivity overall (P =.001); and white sibling pairs had significantly lower total serum IgE (P <.05). In addition, there were significantly more relatives with asthma among the African American families than among the white and the Hispanic families (P =.001). CONCLUSION: Although different environmental backgrounds should be considered, these clinical differences could be due to differences in genetic susceptibility among the ethnic groups, such as those suggested by our previous genome screen.

Adolescent↗
PubMed2001

Subjects with mild and moderate asthma respond to segmental allergen challenge with similar, reproducible, allergen-specific inflammation.

BACKGROUND: The relationship between severity of asthma and bronchial inflammation is poorly understood. OBJECTIVE: We examined acute and subacute inflammatory responses to allergen in subjects with mild and moderate persistent asthma to evaluate whether different cellular and mediator responses to endobronchial allergen challenge are associated with differences in disease severity. METHODS: Segmental allergen challenge was performed in 8 subjects with mild and 10 subjects with moderate allergic asthma to compare baseline airways inflammation and allergen-induced inflammatory responses 24 hours later. This evaluation was repeated after 6 weeks in 9 subjects to investigate the reproducibility of these inflammatory responses. RESULTS: Subjects with mild and moderate asthma had similar decreases in FEV(1) in response to segmental allergen challenge (9.1% +/- 4.2% vs 15.1% +/- 4.6%, P = .35). There was no difference in inflammatory cell counts or cytokine concentrations in the groups with mild and moderate asthma at baseline or after saline or allergen challenge. Repeat segmental allergen challenge 6 weeks later showed that these cellular and cytokine responses were reproducible. CONCLUSION: Segmental allergen challenge in subjects with mild and moderate asthma produces similar allergen-specific physiologic and inflammatory responses that are reproducible 6 weeks later. In this model of allergic asthma, acute responses to allergen do not appear to be related to disease severity.

Adult↗
PubMed2001

Association of a promoter polymorphism of the CD14 gene and atopy.

Atopy is generally considered to be caused by interaction of genetic and environmental factors. Recently, an association of a C-to-T transition in the promoter region of the CD14 gene on chromosome 5q31.1 and atopic phenotypes was reported in a population study of school children in the United States. The aim of the present study was to investigate the association of the C allele of the CD14/-159 with phenotypes of atopy and asthma in an adult Dutch population in which linkage of total serum IgE and bronchial hyperresponsiveness to chromosome 5q31-33 is present. We studied 159 probands with asthma and 158 spouses as controls. Phenotypes for asthma (e.g., bronchial hyperresponsiveness, physician's diagnosis) and for atopy (e.g., total serum IgE level, intracutaneous skin test, allergic rhinitis) were studied. In this population, homozygotes for the C allele had a higher number of positive skin tests and higher total serum IgE levels (in skin test-positive individuals) and subsequently, more self-reported allergic symptoms including rhinitis and hay fever, compared with subjects with CT and TT alleles. We conclude that the -159 C-to-T promoter polymorphism in the CD14 gene may result in expression of a more severe allergic phenotype.

Adult↗
PubMed2001

Identification and association of polymorphisms in the interleukin-13 gene with asthma and atopy in a Dutch population.

Asthma and atopy are related conditions that may share similar genetic susceptibility. Linkage studies have identified a region on chromosome 5q that contains biologic candidates for both asthma and atopy phenotypes, including several proinflammatory cytokines. Interleukin (IL)-13, one of the candidate genes in the region, is directly involved in the regulation of immunoglobulin E and has been associated with both asthma and atopy. We sought to identify new polymorphisms in the IL-13 gene, and evaluated the involvement of a subset of these variants in asthma and atopy in a case-control study using probands and spouses from a Dutch asthma family study. IL-13 was sequenced in 20 probands and 20 unaffected spouses, and 10 polymorphisms were identified, four novel and six previously reported. Three single nucleotide (nt) polymorphisms (SNPs) were detected in the 5'-promoter region, two in intron 1, and five in exon 4. Only one of the exon 4 SNPs resulted in an amino-acid change (Arg130Gln). We analyzed three SNPs in IL-13 in an extended group of 184 probands and their spouses: one in the promoter region (-1111), the Arg130Gln (nt position 4257), and a 3' untranslated region SNP (nt position 4738). The most significant associations were observed to asthma (P = 0.005), bronchial hyperresponsiveness (P = 0.003), and skin-test responsiveness (P = 0.03) with the -1111 promoter. These results provide evidence that variation in the IL-13 gene is involved in the pathogenesis of asthma and atopy. Further investigation is required to determine which specific alleles or combination of alleles contribute to these phenotypes, and the possible downstream effects of the resulting change in IL-13 levels or activity.

Adult↗
PubMed2000

Major genes regulating total serum immunoglobulin E levels in families with asthma.

Immunoglobulin E (IgE) has a major role in the pathogenesis of allergic disorders and asthma. Previous data from 92 families, each identified through a proband with asthma, showed evidence for two major genes regulating total serum IgE levels. One of these genes mapped to 5q31-33. In the current study, the segregation analysis was extended by the addition of 108 probands and their families, ascertained in the same manner. A mixed recessive model (i.e., major recessive gene and residual genetic effect) was the best-fitting and most-parsimonious one-locus model of the segregation analysis. A mixed two-major-gene model (i.e., two major genes and residual genetic effect) fit the data significantly better than did the mixed recessive one-major-gene model. The second gene modified the effect of the first recessive gene. Individuals with the genotype aaBB (homozygous high-risk allele at the first gene and homozygous low-risk allele at the second locus) had normal IgE levels (mean 23 IU/ml), and only individuals with genotypes aaBb and aabb had high IgE levels (mean 282 IU/ml). A genomewide screening was performed using variance-component analysis. Significant evidence for linkage was found for a novel locus at 7q, with a multipoint LOD score of 3. 36 (P=.00004). A LOD score of 3.65 (P=.00002) was obtained after genotyping additional markers in this region. Evidence for linkage was also found for two previously reported regions, 5q and 12q, with LOD scores of 2.73 (P=.0002) and 2.46 (P=.0004), respectively. These results suggest that several major genes, plus residual genetic effects, regulate total serum IgE levels.

Adolescent↗