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Biomedical subjects

Eugene R Bleecker

Publications and source records attributed to Eugene R Bleecker.

At least 55 records · Page 3Linked to original sources
PubMed2003

Association between genetic polymorphisms in the prostate-specific antigen gene promoter and serum prostate-specific antigen levels.

BACKGROUND: Recent evidence suggests that genetic variation in the promoter of the prostate-specific antigen (PSA) gene may contribute to individual variation in serum PSA levels. However, polymorphisms associated with variations in PSA levels have not been identified. METHODS: We used the polymerase chain reaction to amplify the promoter region of the PSA genes (nucleotide positions -3873 to -5749 with respect to the start of transcription) of 409 healthy white men at risk for lung disease. Polymerase chain reaction products were sequenced to identify polymorphisms in the PSA gene promoter and to genotype the men for common single nucleotide polymorphisms (SNPs) and were cloned into luciferase reporter constructs to assay PSA promoter activity in human LNCaP prostate cancer cells. Analysis of variance was used to test the association of polymorphism frequencies with mean serum PSA levels. All statistical tests were two-sided. RESULTS: The -4643G/A SNP (G allele) had a 21.2% prevalence and was associated with increases in serum PSA levels (P =.017) and PSA promoter activity (P<.001). The -5412C/T SNP (C allele) had a 22.0% prevalence and was associated with an increase in serum PSA levels (P =.0015). The -5429T/G SNP (G allele) had a 23.0% prevalence, was associated with an increase in serum PSA levels (P =.021), and was in linkage disequilibrium with the -5412C/T SNP. The promoter activity of the -5412 C/-5429 G haplotype was higher than that of the -5412 T/-5429 T haplotype (P<.001). CONCLUSIONS: Genetic variations in the PSA promoter are associated with serum PSA levels in men without prostatic disease. PSA promoter genotype information may help to refine models of PSA cutoff values.

Aged↗
PubMed2003

Evaluation of SRD5A2 sequence variants in susceptibility to hereditary and sporadic prostate cancer.

BACKGROUND: The 5 alpha-reductase type II (SRD5A2) catalyzes the conversion of testosterone into the more potent androgen, dihydrotestosterone (DHT), and is thus believed to be the key enzyme for the control of intracellular DHT level in the prostate. Several single nucleotide polymorphisms (SNPs) in the SRD5A2 gene have been found to alter enzymatic activities and were associated with prostate cancer risk or clinical features in several case-control studies. However, the role of SRD5A2 sequence variants in the susceptibility to hereditary prostate cancer (HPC) has not been evaluated to date. METHODS: Three SNPs in the SRD5A2 gene (A49T, V89L, and C682G) and two microsatellite markers near SRD5A2 were genotyped in 159 HPC families to assess their linkage to prostate cancer. In addition, the three SNPs were also genotyped in 245 sporadic cases and 222 unaffected controls to assess their association with hereditary and sporadic prostate cancer. RESULTS: Weak evidence for linkage in the SRD5A2 chromosomal region was observed in the 159 HPC families (HLOD = 0.87, P = 0.04). Stronger evidence for linkage was observed in Caucasian families (HLOD = 1.10, P = 0.02). When stratified by the SNP A49T, no significant evidence for linkage was observed in families with or without the "T" allele. Similarly, family-based association tests failed to observe significant over-transmission of any risk alleles of SNPs A49T, V89L, and C682G to affected offspring. Finally, no significant differences in the distributions of SNPs A49T, V89L, and C682G were found among the HPC probands, sporadic cases, and controls. CONCLUSIONS: Polymorphisms of SRD5A2 are unlikely to significantly increase susceptibility to hereditary or sporadic prostate cancer in the study populations.

Aged↗
PubMed2003

Association of a disintegrin and metalloprotease 33 (ADAM33) gene with asthma in ethnically diverse populations.

BACKGROUND: Asthma is a complex genetic disease characterized by reversible intermittent airway obstruction and respiratory symptoms primarily caused by acute and chronic bronchial inflammation. Recently, a gene potentially involved in airway remodeling, a disintegrin and metalloprotease 33 (ADAM33), was implicated in asthma susceptibility. OBJECTIVE: We sought to determine whether polymorphisms in ADAM33 are associated with asthma or closely related phenotypes in 4 different asthma populations. METHODS: Eight single nucleotide polymorphisms (SNPs) were evaluated in the 3' portion of ADAM33 in 4 unique asthma populations (African American, US white, US Hispanic, and Dutch white). These SNPs were previously reported to be associated with asthma in white populations from the United States and United Kingdom. RESULTS: Significant associations were observed with at least one SNP and asthma in each population (P =.0009-.04). Related phenotypes that included total serum IgE levels and skin test responsiveness were also associated (P =.003-.05). However, no single SNP was associated across all populations. Additionally, haplotype analysis revealed that no single haplotype accounted for asthma susceptibility risk, although potential risk haplotypes existed within some of the populations. CONCLUSION: Replication of the original ADAM33 findings in these 4 additional asthma populations suggests that this gene (and perhaps others that interact with it) is important in the development and pathogenesis of asthma.

ADAM Proteins↗
PubMed2003

Evidence for gene-environment interactions in a linkage study of asthma and smoking exposure.

BACKGROUND: Asthma, a common and chronic disease of the airways, has a multifactorial cause involving both genetic and environmental factors. As a result, mapping genes that influence asthma susceptibility has been challenging. OBJECTIVE: This study tests the hypothesis that inclusion of exposure to environmental tobacco smoke (ETS), a potential risk factor for asthma, would improve the ability to map genes for asthma. METHODS: By using 144 white families from the Collaborative Study for the Genetics of Asthma, environmental information about exposure to ETS during infancy was incorporated into a genome-wide multipoint linkage analysis. Statistical significance of observed gene-environment interactions was assessed by means of simulation. RESULTS: Three regions with nominal evidence for linkage when stratified on the basis of ETS exposure were identified (P <.01) and showed a significant increase from the baseline lod score (1p at 97 cM, D1S1669-D1S1665; 5q at 135 cM, D5S1505-D5S816; and 9q at 106 cM, D9S910; all P <.05). In addition, 2 other regions, although not meeting nominal significance after stratification on the basis of ETS exposure, showed a significant increase from baseline lod score when ETS was taken into account (1q at 240 cM, D1S549; 17p at 3 cM, D17S1308; all P <.01). CONCLUSION: These results illustrate how evidence for linkage of asthma can depend on exposure to an environmental factor, such as ETS. Future linkage analyses should include information on suspected environmental factors for asthma to help target new candidate susceptibility genes for asthma.

Adult↗
PubMed2003

Mapping susceptibility genes for allergic diseases.

Allergic diseases are most likely due to interactions between genetic and environmental factors. While many of the environmental components have been studied for years, only recently has significant progress been made in identifying the genes responsible for susceptibility or expression of these diseases. Genome-wide screens in various populations have identified the locations of susceptibility genes for asthma and atopy, as well as associated phenotypes such as bronchial hyperresponsiveness and increased total serum IgE levels. In addition, this positional cloning approach has led to the discovery of several genes for asthma or related phenotypes, which is extending our understanding of the pathophysiology of allergic diseases. As these genes are identified and characterized, the relationships of these genes to each other and the environment will become important areas of research. Understanding the basic interactions that lead to the development of allergy and asthma will lead to new therapeutic approaches that will be used to modify the development and clinical progression of these common disorders.

Asthma↗
PubMed2002

Common sequence variants of the macrophage scavenger receptor 1 gene are associated with prostate cancer risk.

Rare germline mutations of macrophage scavenger receptor 1 (MSR1) gene were reported to be associated with prostate cancer risk in families with hereditary prostate cancer (HPC) and in patients with non-HPC (Xu et al. 2002). To further evaluate the role of MSR1 in prostate cancer susceptibility, at Johns Hopkins Hospital, we studied five common variants of MSR1 in 301 patients with non-HPC who underwent prostate cancer treatment and in 250 control subjects who participated in prostate cancer-screening programs and had normal digital rectal examination and PSA levels (<4 ng/ml). Significantly different allele frequencies between case subjects and control subjects were observed for each of the five variants (P value range.01-.04). Haplotype analyses provided consistent findings, with a significant difference in the haplotype frequencies from a global score test (P=.01). Because the haplotype that is associated with the increased risk for prostate cancer did not harbor any of the known rare mutations, it appears that the observed association of common variants and prostate cancer risk are independent of the effect of the known rare mutations. These results consistently suggest that MSR1 may play an important role in prostate carcinogenesis.

Case-Control Studies↗
PubMed2002

Sequence variants of alpha-methylacyl-CoA racemase are associated with prostate cancer risk.

The enzyme alpha-methylacyl-CoA racemase (AMACR) plays an important role in peroxisomal beta-oxidation of branched-chain fatty acid and therefore is relevant to carcinogenesis. The involvement of AMACR in prostate cancer (CaP) is implicated by the recent observation that expression of AMACR is consistently and extensively up-regulated in CaP. This observation is of particular interest, given previous findings from epidemiological studies that red meat and dairy products, major sources of branched-chain fatty acid, are associated with CaP risk and from linkage studies that the AMACR gene region at 5p13 is linked to a CaP susceptibility gene. In this study, we hypothesize that sequence variants in AMACR may alter the risk for CaP. To test this hypothesis, we sequenced all five exons, exon-intron junctions, the promoter region, and 3'-untranslated region of AMACR in germ-line DNA samples of 96 probands from hereditary CaP (HPC) families. Seventeen sequence variants, including five novel (R118Q, V185A, P238S, Q239H, and L250R) and five known (M9V, S52P, D175G, S201L, and K277E) missense changes, were identified. Six of these variants are at conserved residues among the rat and mouse AMACR. Eleven of these single nucleotide polymorphisms were genotyped in a total of 159 HPC probands, 245 sporadic cases, and 211 unaffected controls to assess their association with CaP risk. Significantly different genotype frequencies between HPC probands and unaffected controls were found for several missense changes, including M9V (P = 0.03), G1175D (P = 0.02), S291L (P = 0.02), and K277E (P = 0.02). Haplotype analysis provided stronger evidence for association (P = 0.001). Furthermore, the AMACR sequence variants strongly cosegregate with CaP in HPC families (log of odds = 3.78; P = 0.00006), especially in the subset of families whose probands carry the "A-A" haplotype of M9V and D175G (log of odds = 4.34; P = 0.000008). These results suggest that sequence variants in AMACR may be associated with CaP risk.

3' Untranslated Regions↗
PubMed2002

Sequence variants in the human 25-hydroxyvitamin D3 1-alpha-hydroxylase (CYP27B1) gene are not associated with prostate cancer risk.

BACKGROUND: 1,25-dihydroxyvitamin D(3) has been shown to have antiproliferative properties on normal and neoplastic prostatic cells. 25-hydroxyvitamin D(3) 1-alpha-hydroxylase, the enzyme that catalyzes the final step of vitamin D synthesis, converting 25-hydroxyvitamin D(3) to 1,25-dihydroxyvitamin D(3), is expressed in the prostate. METHODS: The human 25-hydroxyvitamin D(3) 1-alpha-hydroxylase gene (CYP27B1) was resequenced in a case/control panel consisting of 64 individuals (48 Caucasians and 16 African Americans), with equal numbers of hereditary prostate cancer cases, sporadic cases, and unaffected controls. Three frequent single nucleotide polymorphisms (SNPs) were genotyped in 245 prostate cancer cases and 222 controls. RESULTS: Six noncoding SNPs were identified in the CYP27B1 gene. No significant difference was found in allele and genotype frequencies between sporadic cases and unaffected controls for the three genotyped SNPs. CONCLUSION: This study suggests that the CYP27B1 gene does not play a major role as a prostate cancer susceptibility gene.

25-Hydroxyvitamin D3 1-alpha-Hydroxylase↗
PubMed2002

Germline mutations and sequence variants of the macrophage scavenger receptor 1 gene are associated with prostate cancer risk.

Deletions on human chromosome 8p22-23 in prostate cancer cells and linkage studies in families affected with hereditary prostate cancer (HPC) have implicated this region in the development of prostate cancer. The macrophage scavenger receptor 1 gene (MSR1, also known as SR-A) is located at 8p22 and functions in several processes proposed to be relevant to prostate carcinogenesis. Here we report the results of genetic analyses that indicate that mutations in MSR1 may be associated with risk of prostate cancer. Among families affected with HPC, we identified six rare missense mutations and one nonsense mutation in MSR1. A family-based linkage and association test indicated that these mutations co-segregate with prostate cancer (P = 0.0007). In addition, among men of European descent, MSR1 mutations were detected in 4.4% of individuals affected with non-HPC as compared with 0.8% of unaffected men (P = 0.009). Among African American men, these values were 12.5% and 1.8%, respectively (P = 0.01). These results show that MSR1 may be important in susceptibility to prostate cancer in men of both African American and European descent.

Aged↗
PubMed2002

Major recessive gene(s) with considerable residual polygenic effect regulating adult height: confirmation of genomewide scan results for chromosomes 6, 9, and 12.

Segregation and linkage analyses were performed for adult height in a population of 200 Dutch families, each of which was ascertained through a proband with asthma. The best-fit model from the segregation analysis was a major recessive gene with a significant residual polygenic background. Models without a polygenic component were rejected. A genomewide scan was performed, and it confirmed previous linkage results for chromosomes 6q25 (LOD = 3.06, D6S2436), 9p1 (LOD = 2.09, D9S301), and 12q1 (LOD = 1.86, D12S375). Our results provide evidence that a combination of segregation and linkage approaches is valuable in understanding genetic determination of common complex traits.

Adolescent↗
PubMed2002

Common estrogen receptor polymorphism augments effects of hormone replacement therapy on E-selectin but not C-reactive protein.

BACKGROUND: The estrogen receptor-alpha (ER-alpha) IVS1-401 polymorphism identifies a group of women (approximately 20%) who have augmented effects of hormone replacement therapy (HRT) on levels of HDL cholesterol. This study sought to determine if this augmentation extends to HRT regulation of E-selectin and C-reactive protein (CRP) and to explore possible mechanisms by which this polymorphism might influence estrogen action. METHODS AND RESULTS: Serum levels of soluble E-selectin and CRP were measured at baseline and 1 year in 264 postmenopausal women randomized to treatment with oral conjugated equine estrogen (0.625 mg/d), estrogen plus progestin (medroxyprogesterone acetate 2.5 mg/d), or placebo. Women with the ER-alpha IVS1-401 C/C genotype receiving HRT had nearly a 2-fold greater reduction in E-selectin compared with C/T or T/T women (P for interaction=0.02). In contrast, there was no augmentation of the HRT-associated increase in CRP among the C/C women compared with C/T or T/T women (P for interaction=0.54). Of luciferase reporter constructs containing sequences spanning the IVS1-401 T/C polymorphism, expression of the construct containing the C allele was enhanced >10-fold, with cotransfection of a constitutively expressed B-myb vector. In contrast, B-myb resulted in only a 2.5-fold increase in expression of the T allele construct. CONCLUSIONS: Women with the ER-alpha IVS1-401 C/C genotype have greater reductions in E-selectin but no further increases in CRP with HRT. The C allele produces a functional binding site for the transcription factor B-myb. The impact of this polymorphism on ER-alpha transcription and other estrogen-sensitive intermediate and clinical end points has not yet been established.

Base Sequence↗
PubMed2002

Associations between hOGG1 sequence variants and prostate cancer susceptibility.

8-Hydroxyguanine is a mutagenic base lesion produced by reactive oxygen species. The hOGG1 gene encodes a DNA glycosylase/AP lyase that can suppress the mutagenic effects of 8-hydroxyguanine by catalyzing its removal from oxidized DNA. A population-based (245 cases and 222 controls) and family-based (159 hereditary prostate cancer families) association study was performed to test the hypothesis that sequence variants of hOGG1 increase susceptibility to prostate cancer. We found that the genotype frequency of two sequence variants (11657A/G and Ser326Cys) was significantly different between cases and controls. The association with 11657A/G is confirmed and strengthened by our family-based association study. These results suggest that sequence variants in this gene are associated with prostate cancer risk, presumably through defective DNA repair function of hOGG1.

Case-Control Studies↗
PubMed2002

Estrogen-receptor polymorphisms and effects of estrogen replacement on high-density lipoprotein cholesterol in women with coronary disease.

BACKGROUND: Sequence variants in the gene encoding estrogen receptor alpha (ER-alpha) may modify the effects of hormone-replacement therapy on levels of high-density lipoprotein (HDL) cholesterol and other outcomes related to estrogen treatment in postmenopausal women. METHODS: We characterized 309 women with coronary artery disease who were enrolled in the Estrogen Replacement and Atherosclerosis trial with respect to eight previously described and two newly identified ER-alpha polymorphisms, and we examined the association between these polymorphisms and the response of HDL cholesterol and other lipids to treatment with estrogen alone or estrogen plus progestin. RESULTS: After adjustment for age, race, diabetes status, body-mass index, smoking status, alcohol intake, and frequency of exercise, the 18.9 percent of the women who had the IVS1-401 C/C genotype (i.e., with C on both chromosomes in intervening sequence 1 at position 401 before exon 2) had an increase in the HDL cholesterol level with hormone-replacement therapy that was more than twice the increase observed in the other women (13.1 mg per deciliter vs. 6.0 mg per deciliter, P for treatment-by-genotype interaction = 0.004); this effect was limited to changes in the HDL subfraction 3 (HDL3) (P for interaction=0.04). Similar patterns of response were observed for three other highly linked ER-alpha intron 1 polymorphisms close to the IVS1-401 site (range of P values for interaction = 0.07 to 0.005). The pattern of increased response of HDL cholesterol in women with the IVS1-401 C/C genotype was evident in both the women receiving estrogen and those receiving estrogen plus progestin, was preserved across racial and ethnic groups, and was significant among women who were compliant with the study medication (P<0.001). CONCLUSIONS: Postmenopausal women with coronary disease who have the ER-alpha IVS1-401 C/C genotype, or several other closely related genotypes, have an augmented response of HDL cholesterol to hormone-replacement therapy.

Cholesterol, HDL↗
PubMed2002

Joint effect of HSD3B1 and HSD3B2 genes is associated with hereditary and sporadic prostate cancer susceptibility.

3beta-hydroxysteroid dehydrogenases (HSD3Bs), encoded by the HSD3B gene family at 1p13, have long been hypothesized to have a major role in prostate cancer susceptibility. The recent reports of a prostate cancer linkage at 1p13 provided additional evidence that HSD3B genes may be prostate cancer susceptibility genes. To evaluate the possible role of HSD3B genes in prostate cancer, we screened a panel of DNA samples collected from 96 men with or without prostate cancer for sequence variants in the putative promoter region, exons, exon-intron junctions, and 3'-untranslated region of HSD3B1 and HSD3B2 genes by direct sequencing. Eleven single nucleotide polymorphisms (SNPs) were identified, four of which, including a missense change (B1-N367T), were informative. These four SNPs were further genotyped in a total of 159 hereditary prostate cancer probands, 245 sporadic prostate cancer cases, and 222 unaffected controls. Although a weak association between prostate cancer risk and a missense SNP (B1-N367T) was found, stronger evidence for association was found when the joint effect of the two genes was considered. Men with the variant genotypes at either B1-N367T or B2-c7519g had a significantly higher risk to develop prostate cancer, especially the hereditary type of prostate cancer. Most importantly, the subset of hereditary prostate cancer probands, whose families provided evidence for linkage at 1p13, predominantly contributed to the observed association. Additional studies are warranted to confirm these findings.

3-Hydroxysteroid Dehydrogenases↗
PubMed2002

Polymorphic GGC repeats in the androgen receptor gene are associated with hereditary and sporadic prostate cancer risk.

Androgen receptor (AR) has long been hypothesized to play an important role in prostate cancer etiology. Two trinucleotide repeat polymorphisms (CAG and GGC repeats in exon 1 of the AR gene) have been investigated as risk factors for prostate cancer in several studies. However, the results are inconclusive, probably because of the variations of study designs, characteristics of study samples, and choices of analytical methods. In this study, we evaluated evidence for linkage and association between the two AR repeats and prostate cancer by using the following comprehensive approaches: (1) a combination of linkage and association studies, (2) a test for linkage by parametric analysis and the male-limited X-linked transmission/disequilibrium test (XLRC-TDT), (3) a test for association by using both population-based and family-based tests, and (4) a study of both hereditary and sporadic cases. A positive but weak linkage score (HLOD=0.49, P=0.12) was identified in the AR region by parametric analysis; however, stronger evidence for linkage in the region, especially at the GGC locus, was observed in the subset of families whose proband had < or = 16 GGC repeats (HLOD=0.70, P=0.07) or by using XLRC-TDT ( z'=2.65, P=0.008). Significantly increased frequencies of the < or = 16 GGC repeat alleles in 159 independent hereditary cases (71%) and 245 sporadic cases (68%) cases compared with 211 controls (59%) suggested that GGC repeats were associated with prostate cancer ( P=0.02). Evidence for the association between the < or = 16 GGC repeats and prostate cancer risk was stronger with XLRC-TDT ( z'=2.66, P=0.007). No evidence for association between the CAG repeats and prostate cancer risk was observed. The consistent results from both linkage and association studies strongly implicate the GGC repeats in the AR as a prostate cancer susceptibility gene. Further studies on this polymorphism in other independent data sets and functional analysis of the GGC repeat length on AR activity are warranted.

Ethnicity↗
PubMed2002

Germline sequence variants of the LZTS1 gene are associated with prostate cancer risk.

The 8p22 through p23 region has been identified as a potential site for genes associated with prostate cancer. The gene LZTS1 has been mapped to the 8p22 through p23 region and identified as a potential tumor suppressor based on loss of heterozygosity studies using primary esophageal tumors. Sequence analysis of mRNA from various tumors has revealed multiple mutations and aberrant mRNA transcripts. The most recent report associates LZTS1 function with stabilization of p34(cdc2) during the late S-G2/M stage of mitosis, affecting normal cell growth. In this study, a detailed DNA sequence analysis of LZTS1 was performed in a screening panel consisting of sporadic and hereditary prostate cancer (HPC) cases and unaffected controls. Twenty-four SNP, 15 of which were novel, were identified in germline DNA. Four coding SNP were identified. Eleven informative SNP were genotyped in 159 HPC probands, 245 sporadic prostate cancer cases, and 222 unaffected controls. Four of these SNP were statistically significant for association with prostate cancer (P < or = 0.04). These results add evidence supporting a role of LZTS1 in prostate cancer risk.

Base Sequence↗
PubMed2002

Genome-wide search for atopy susceptibility genes in Dutch families with asthma.

BACKGROUND: Atopy is a phenotype associated with asthma that has a heritable component. However, the role of atopysusceptibility genes in the development and expression of asthma and allergic disorders is not understood. OBJECTIVE: We sought to study the familial aggregation and co-occurrence of atopic phenotypes within family members of patients with asthma and to identify chromosomal regions that may contain genes that regulate different atopic phenotypes. METHODS: In 200 families (n = 1174) ascertained through a proband with asthma, genome-wide screen and linkage analysis was performed for the following atopic phenotypes: (1) specific IgE to common aeroallergens (Phadiatop assay); (2) specific IgE to Der p 1; (3) positive skin test responses to house dust mite; (4) positive skin test responses to 1 or more of 16 allergens; and (5) peripheral blood eosinophils. Results were compared with the linkage results for total serum IgE levels. RESULTS: There was clear familial aggregation of atopy. A high total serum IgE level in combination with a positive Phadiatop result or a normal total IgE level in combination with a negative Phadiatop result was found in 56.1% of the probands and 66.9% of the offspring. Several chromosomal regions that showed evidence for linkage to an atopic phenotype (ie, 2q, 6p, 7q, and 13q) also showed evidence of linkage with total serum IgE (Xu et al. Am J Hum Genet 2000;67:1163-73). Specific regions of interest for atopic traits were also detected on chromosomes 11q, 17q, and 22q. CONCLUSIONS: Atopic phenotypes show familial aggregation, although family members may differ in expression of atopy. Specific chromosomal regions appear to be important in susceptibility to different phenotypes of atopic responsiveness.

Adolescent↗