PubMed Health⌕ Search

Biomedical subjects

Edwin H Cook

Publications and source records attributed to Edwin H Cook.

At least 37 records · Page 2Linked to original sources
PubMed2005

A functional common polymorphism in a Sp1 recognition site of the epidermal growth factor receptor gene promoter.

The epidermal growth factor receptor (EGFR) plays a prominent role in cell growth and development. Its regulation in humans is complex and incompletely understood. In this study, 12 new polymorphisms were discovered in the 5'-regulatory region of EGFR gene and 2 common single nucleotide polymorphisms (-216G/T and -191C/A) were found in the essential promoter area, one of which is located in a Sp1 recognition site (-216). Transient transfection in human cancer and primary cell lines showed significantly different promoter activity between the two most common haplotypes (-216G-191C and -216T-191C). The replacement of G by T at position -216 increases the promoter activity by 30%. A transient transfection assay in the Sp1-deficient cell line (Schneider cell line 2) showed a strong dependence of EGFR promoter activity on Sp1 and confirmed the effect of the aforementioned polymorphisms. Electrophoretic mobility shift assay also showed a significantly higher binding efficiency of nuclear protein or pure Sp1 protein to the T allele compared with the G allele. We then investigated the allelic imbalance of EGFR transcription in fibroblast cell lines with heterozygous genotype at -216G/T but C/C homozygous genotype at -191C/A. The expression of mRNA carrying T-C haplotype was significantly stronger compared with that of G-C haplotype (P < 0.02). Thus, we successfully showed that a common polymorphism in the EGFR promoter was associated with altered promoter activity and gene expression both in vitro and in vivo. Our findings have implications for cancer etiology and therapy and may also be relevant to the inherited susceptibility of other common diseases.

Base Sequence↗
PubMed2005

Dopamine transporter gene associated with diminished subjective response to amphetamine.

Individual variability in responses to stimulant drugs may influence risk of stimulant abuse and treatment response. However, the genetic determinants of this variability have yet to be elucidated. The dopamine transporter is an important site of amphetamine action. Therefore, the dopamine transporter gene (DAT1) is a logical candidate gene to study. Using a drug challenge approach, we tested for association between DAT1 genotype and subjective responses to amphetamine in healthy adults. Volunteers participated in a double-blind, crossover design, randomly receiving placebo, 10 mg, and 20 mg oral D-amphetamine, and completed self-report measures on subjective effects including anxiety and euphoria. Subjects were genotyped for the DAT1 3'-untranslated region VNTR polymorphism and divided into groups based on genotype: homozygous for nine repeats (9/9, N=8), heterozygous (9/10, N=36) and homozygous for 10 repeats (10/10, N=52). The effects of amphetamine on ratings of Feel Drug, Anxiety, and Euphoria were examined with ANCOVA. In 9/10 and 10/10 subjects, amphetamine produced its expected effects of increased Euphoria, Anxiety, and Feel Drug (p<0.01). However, in 9/9 subjects, the effects of amphetamine were indistinguishable from placebo, suggesting that the 9/9 genotype has diminished subjective response to acute amphetamine. Interestingly, recent findings also implicate the 9/9 genotype in decreased therapeutic response to the stimulant methylphenidate in ADHD children. The current findings have important implications for understanding the genetic determinants of variability in stimulant response and risk of abuse.

3' Untranslated Regions↗
PubMed2005

Dopamine transporter genotype and methylphenidate dose response in children with ADHD.

Stimulant medications, such as methylphenidate (MPH), are the most commonly used, effective treatment for ADHD. MPH acts primarily by inhibiting the dopamine transporter (DAT), a protein responsible for the reuptake of dopamine from the synapse into presynaptic terminals. We sought to evaluate the relationship between DAT1 3'-untranslated region (3'-UTR) variable number tandem repeats (VNTR) genotypes and dose response to MPH. Children with ADHD (n=47), ages 5-16 years (mean=9.02 years), underwent a 4-week, double-blinded, crossover trial with forced weekly dosage changes. Children were genotyped for the DAT1 VNTR and evaluated on placebo and three dosage levels of OROS MPH. Parents and clinicians who were blind to genotype and medication status rated ADHD symptoms, impairment, and stimulant side effects each week. Children who were homozygous for the less common, 9-repeat DAT1 3'-UTR genotype displayed a distinct dose-response curve from that of the other genotype groups, with an absence of typical linear improvement when the dose was increased from 18 mg to 36 and 54 mg. Further research is needed to determine the mechanisms related to poor response in patients with the 9/9-repeat genotype, and to determine if this group responds differentially to alternative treatments.

3' Untranslated Regions↗
PubMed2005

A double-blind, placebo-controlled study of valproate for aggression in youth with pervasive developmental disorders.

OBJECTIVE: The aim of this study was to study valproate efficacy and safety for aggression in children and adolescents with pervasive developmental disorders (PDD). METHODS: In this prospective double-blind, placebo-controlled study, 30 subjects (20 boys, 10 girls) 6-20 years of age with PDD and significant aggression were randomized and received treatment with valproate (VPA) or placebo (PBO) for 8 weeks as outpatients. Mean VPA trough blood levels were 75.5 mcg/mL at week 4 and 77.8 mcg/mL at week 8. RESULTS: No treatment difference was observed statistically between VPA and PBO groups. The Aberrant Behavior Checklist--Community Scale (ABC-C) Irritability subscale was the primary outcome measure (p = 0.65), and CGI--Improvement (p = 0.16) and OAS (p = 0.96) were secondary outcome measures. Increased appetite and skin rash were significant side effects. Only 1 subject was dropped from the study owing to side effects, notably a spreading skin rash, which then resolved spontaneously. Two subjects receiving VPA developed increased serum ammonia levels, one with an associated parent report of slurred speech and mild cognitive slowing. Poststudy, of 16 VPA and PBO subjects receiving VPA, 10 subjects demonstrated sustained response, 4 of whom later attempted taper, with significant relapse of aggression. CONCLUSION: The present negative findings cannot be viewed as conclusive, partly owing to the large placebo response, subject heterogeneity, and size of the groups. Larger studies are needed to expand upon these findings.

Adolescent↗
PubMed2005

An open-label trial of escitalopram in pervasive developmental disorders.

OBJECTIVE: To assess the effect of escitalopram in the treatment of pervasive developmental disorders (PDDs). METHOD: This 10-week study had a forced titration, open-label design. Twenty-eight subjects (mean age 125.1 +/- 33.5 months) with a PDD received escitalopram at a dose that increased weekly to a maximum dose of 20 mg as tolerated. The Aberrant Behavior Checklist-Community Version (ABC-CV) and the Clinical Global Impression scale (CGI) were used to assess outcome. RESULTS: There was significant improvement in ABC-CV Irritability Subscale Scores (baseline mean 20.5 +/- 5.9 to final mean 10.9 +/- 7.2; p < or = .001) and in the other ABC-CV Subscales. Improvement on Clinical Global Improvement Scale severity rating was also significant (baseline mean 5.2 +/- 1.0 to final mean 4.6 +/- 1.2; p < or = .001). Twenty-five percent of the subjects responded at a dose less than 10 mg and did not tolerate the 10-mg dose, and an additional 36% responded at a dose greater than or equal to 10 mg. Final dose was unrelated to weight and only weakly correlated with age. CONCLUSIONS: This open-label study found escitalopram to be useful in treating some difficulties common in PDDs. A wide variability in dose was found that could not be accounted for by weight and only partially by age. The study provides information useful for the design of double-blind, placebo-controlled studies of escitalopram in PDDs.

Adolescent↗
PubMed2005

Are the arginine vasopressin V1a receptor microsatellites related to hypersexuality in children with a prepubertal and early adolescent bipolar disorder phenotype?

OBJECTIVE: To examine family-based transmission of the number of 5' flanking arginine vasopressin V1a receptor (AVPR1A) microsatellites, which include [(GATA)(14)] and complex [(CT)(4)-TT-(CT)(8)-(GT)(24)] repeats, in probands with a prepubertal and early adolescent bipolar disorder phenotype (PEA-BP). Preferential transmission of the number of AVPR1A microsatellite repeats to hypersexual and uninhibited people-seeking probands was hypothesized, based on reports from preclinical work in the literature. METHODS: Probands were 83 participants in an ongoing controlled study of PEA-BP. The PEA-BP phenotype was defined by DSM-IV mania with at least one of the cardinal symptoms of mania (elation and/or grandiosity) to avoid diagnosing mania only by symptoms that overlapped with those for attention-deficit hyperactivity disorder (ADHD). Comprehensive assessment of the probands included separate Washington University in St. Louis Kiddie Schedule for Affective Disorders and Schizophrenia (WASH-U-KSADS) interviews of parents about their children and of children about themselves. Hypersexuality and uninhibited people-seeking were assessed from the corresponding WASH-U-KSADS items. Microsatellite genotyping of the AVPR1A repeats was conducted using fluorescently labeled primers and detected by laser-induced fluorescence. Alleles were determined with the assistance of semi-automated allele-calling software. There were 32 complete, biological trios (28 informative families) for the GATA repeat and 34 complete, biological trios (30 informative families) for the complex repeat. Data were analyzed using case-control and family-based association methods. RESULTS: Preferential transmission of AVPR1A GATA or complex repeats was not significant for hypersexuality or uninhibited people-seeking, using the transmission disequilibrium test. Similarly, case-control analyses found no significant associations between hypersexuality or uninhibited people-seeking and the number of AVPR1A GATA or complex repeats. For p < 0.05, there was about 80% power to detect odds ratios of 5.0 and 4.0 (in the family-based analyses) and 3.5 and 2.6 (in the case-control analyses), for allele frequencies of 0.1 and 0.5, respectively. CONCLUSION: Preferential transmission of AVPR1A to hypersexual or uninhibited people-seeking probands was not supported.

Adolescent↗
PubMed2004

Sex-specific genetic architecture of whole blood serotonin levels.

Recently, a quantitative-trait locus (QTL) for whole blood serotonin level was identified in a genomewide linkage and association study in a founder population. Because serotonin level is a sexually dimorphic trait, in the present study, we evaluated the sex-specific genetic architecture of whole blood serotonin level in the same population. Here, we use an extended homozygosity-by-descent linkage method that is suitable for large complex pedigrees. Although both males and females have high broad heritability (H2=0.99), females have a higher additive component (h2=0.63 in females; h2=0.27 in males). Furthermore, the serotonin QTL on 17q that was identified previously in this population, integrin beta 3 (ITGB3), and a novel locus on 2q influence serotonin levels only in males, whereas linkage to a region on chromosome 6q is specific to females. Both sexes contribute to linkage signals on 12q and 16p. There were, overall, more associations meeting criteria for suggestive significance in males than in females, including those of ITGB3 and the serotonin transporter gene (5HTT). This analysis is consistent with heritable sexual dimorphism in whole blood serotonin levels resulting from the effects of a combination of sex-specific and sex-independent loci.

Adolescent↗
PubMed2004

Pharmacogenetic risk factors for osteonecrosis of the hip among children with leukemia.

PURPOSE: One of the adverse effects of therapy for acute lymphoblastic leukemia (ALL) is osteonecrosis of the hip. Putative risk factors for osteonecrosis have included being female, white race, and older age. Our goal was to define possible genetic risk factors for osteonecrosis among children treated for newly diagnosed ALL. METHODS: Using a candidate gene approach, we determined the genotypes for 16 common polymorphisms in genes likely to affect the pharmacokinetics or pharmacodynamics of antileukemic medications in 64 children with ALL. Therapy included glucocorticoids and antifolates. Magnetic resonance imaging of both hips was used to diagnose osteonecrosis, and was performed at similar times from the start of ALL therapy (P =.61) in the 25 patients with and the 39 patients without osteonecrosis (median, 447 days and 443 days, respectively). RESULTS: In addition to age older than 10 years (odds ratio [OR], 24.2; P =.0001) and white race (OR, 11.1; P =.037), host factors for osteonecrosis included the vitamin D receptor FokI start site CC genotype (OR, 4.5; P =.045), and the thymidylate synthase low activity 2/2 enhancer repeat genotype (OR, 7.4; P =.049). CONCLUSION: Because folate-related and vitamin D-receptor genetic variants have been associated with bone and vasculature morbidity, these pharmacogenetic associations likely reflect the interaction of antileukemic medications with germline sensitivity to drug actions, and might identify ALL patients at highest risk to develop osteonecrosis.

Age Factors↗
PubMed2004

MECP2 structural and 3'-UTR variants in schizophrenia, autism and other psychiatric diseases: a possible association with autism.

Mutations in the gene coding for methyl-CpG-binding protein 2 (MECP2) cause Rett syndrome (RTT) and have also been reported in a number of X-linked mental retardation syndromes. Furthermore, putative mutations recently have been described in a few autistic patients and a boy with language disorder and schizophrenia. In this study, DNA samples from individuals with schizophrenia and other psychiatric diseases were scanned in order to explore whether the phenotypic spectrum of mutations in the MECP2 gene can extend beyond the traditional diagnoses of RTT in females and severe neonatal encephalopathy in males. The coding regions, adjacent splicing junctions, and highly conserved segments of the 3'-untranslated region (3'-UTR) were examined in 214 patients, including 106 with schizophrenia, 24 with autism, and 84 patients with other psychiatric diseases by detection of virtually all mutations-single strand conformation polymorphism (SSCP) (DOVAM-S). To our knowledge, this is the first analysis of variants in conserved regions of the 3'-UTR of this gene. A total of 5.2 kb per haploid gene was analyzed (1.5 Mb for 214 patients). A higher frequency of missense and 3'-UTR variants was found in autism. One missense and two 3'-UTR variants were found in 24 patients with autism versus one patient with a missense change in 144 ethnically similar individuals without autism (P = 0.009). These mutations suggest that a possible association between MECP2 mutations and autism may warrant further study.

3' Untranslated Regions↗
PubMed2004

Heritability and linkage analysis of sensitivity to cisplatin-induced cytotoxicity.

Little is known about the genetic determinants explaining variation in sensitivity to chemotherapeutic cytotoxicity. We characterized the degree of cisplatin sensitivity, using lymphoblastoid cell lines derived from 10 Centre d'Etude du Polymorphisme Humain pedigrees. We estimated the heritability for susceptibility to cisplatin-induced cytotoxicity to be approximately 0.47; therefore, sensitivity to the cytotoxic effects of cisplatin is under appreciable genetic influence. Linkage analysis was performed, and the strongest signal (lod score, 2.16; empirical P = 0.0005) was found on chromosome 1 at 44 cM. Susceptibility to cisplatin-induced cytotoxicity is likely due to multiple loci, with low locus-specific heritability contributing to the trait. These data show the power of using large pedigrees that have been extensively genotyped for evaluating the genetic contribution to sensitivity to cell growth inhibition by anticancer agents.

Antineoplastic Agents↗
PubMed2004

Genome-wide association study identifies ITGB3 as a QTL for whole blood serotonin.

Serotonin has been implicated in common disorders involving the central nervous, gastrointestinal, cardiovascular, and pulmonary systems. We describe the first genome-wide screen to identify quantitative trait loci (QTLs) influencing whole blood serotonin in 567 members of a single large pedigree, using a novel association-based mapping approach. We identified an association between the beta3 integrin (ITGB3) Leu33Pro polymorphism on 17q21 and whole blood serotonin levels (P-value = 9.8 x 10(-5)). This variant explained the evidence for linkage in this region when included as a covariate in the linkage analysis (change in LOD from 1.87 to 0.16), indicating that ITGB3 may be an important serotonin QTL.

Female↗
PubMed2004

Determination and analysis of single nucleotide polymorphisms and haplotype structure of the human carboxylesterase 2 gene.

Carboxylesterases are members of the serine esterase super family important in the metabolism of a wide variety of substrates, including xenobiotics and prodrugs. There are two known carboxylesterases expressed in human liver, small intestine and other tissues, carboxylesterase 1 (CES1) and carboxylesterase 2 (CES2). The aim of this study was to identify polymorphisms in the CES2 gene and determine whether these polymorphisms affect expression levels of CES2 or rate of metabolism of irinotecan (7-ethyl-10-[4-(1-piperidino)-1-piperidino] carbonyloxy-camptothecin). Microsome samples prepared from liver tissues of 78 normal individuals were used to determine the rate of hydrolysis of irinotecan and procaine (an anaesthetic hydrolysed by CES2 but not CES1). The rate of hydrolysis of irinotecan is highly variable among individuals, ranging from 2.7-138 pmol/mg protein/h (mean +/- SD 26.0 +/- 22.9). Fifteen single nucleotide polymorphisms (SNPs) were identified, one is in an exon, 9 are in introns, three are in the 3'-untranslated region (UTR), and two are in the 5'-flanking region. Eight of the 15 SNP loci have rare allele frequencies greater than 5%, of which three were greater than 20%. Genotyping of samples from the SNP Consortium demonstrated different distributions among African-Americans, Asian-Americans and European-Americans. We also analysed the haplotype structure and estimated linkage disequilibrium (LD). A SNP located in the 5'-UTR (5'-UTR-363) was found in LD with loci in intron 1 (Intron1 + 947, Intron1 + 1361, Intron1 + 1643). Haplotypes with homozygous rare alleles on these loci exhibit lower mRNA levels as determined by real time polymerase chain reaction (P < 0.01) and the incorporation of rare alleles in haplotypes correlate with reduced mRNA (P = 0.03). The 5'-UTR-363 SNP is located in one of the three promoters of CES2. However, we did not observe significant differences in CES2 activities (irinotecan and procaine hydrolysis) among individuals with different haplotypes.

3' Untranslated Regions↗
PubMed2004

Mutation scanning of the androgen receptor gene in patients with psychiatric disorders reveals highly conserved variants in alcoholic and phobia patients.

Sex steroids exert potent effects on mood and mental state in humans. They may contribute to the risk of psychiatric disorders. To investigate this hypothesis, coding and splice junction sequences of the androgen receptor gene were scanned in genomic DNA samples to search for variants affecting protein structure and expression (VAPSEs). Ninety-six schizophrenics, along with pilot samples of patients with bipolar disorder, attention-deficit hyperactivity disorder, alcoholism and autism were analyzed with DOVAM-S, a robotically enhanced, optimized form of single-strand conformation polymorphism analysis. A total of 669 kb of genomic sequence was analyzed. Two VAPSEs were identified: R726L was found in one of 17 scanned alcoholics, and P516S, a novel VAPSE, was identified in one of three phobia patients. There were no length trends of the CAG triplets associated with schizophrenia. R726L and P516S occur at highly conserved amino acids. Further study is required to assess whether these VAPSEs contribute to the risk of alcoholism or phobia or other diseases.

Alcoholism↗
PubMed2004

Autism as a paradigmatic complex genetic disorder.

Autism is one of the most heritable complex disorders, with compelling evidence for genetic factors and little or no support for environmental influence. The estimated prevalence of autism has increased since molecular genetic studies began, owing to loosening of diagnostic criteria and, more importantly, to more complete ascertainment strategies. This has led to a reduction in the sibling relative risk, but strong heritability estimates remain. It is essential to recognize that genetics is the only current approach to understanding the pathophysiology of autism in which there is not the usual concern about whether one is studying a consequence rather than a cause. There are hundreds, if not thousands, of patients with autism spectrum disorder with documented single-gene mutations or chromosomal abnormalities. Autism may be one of the most complex, yet strongly genetic, disorders in which chromosomal disorders, relatively rare highly penetrant mutations, and multiplicative effects of common variants all have support in different cases and families. The field of complex genetics is replete with many researchers and reviewers who want to promote their overly focused interest in one method at the exclusion of others. However, it is essential that the restricted interests of patients with autism not be reflected in overly restrictive genetic approaches if we are to better understand the genetics of autism in the most expeditious and thorough manner.

Alleles↗
PubMed2004

Linkage disequilibrium of the brain-derived neurotrophic factor Val66Met polymorphism in children with a prepubertal and early adolescent bipolar disorder phenotype.

OBJECTIVE: Transmission of the brain-derived neurotrophic factor (BDNF) Val66 allele in children with a prepubertal and early adolescent bipolar disorder phenotype was examined. METHOD: The prepubertal and early adolescent bipolar disorder phenotype was defined as current DSM-IV bipolar I disorder (manic or mixed phase) with at least one cardinal mania criterion (i.e., euphoria and/or grandiosity) to ensure differentiation from attention deficit hyperactivity disorder. Probands (mean age=10.7 years, SD=2.7) were obtained by consecutive new case ascertainment from designated pediatric and psychiatric venues. Parents and probands were interviewed separately by research nurses who were blind to the probands' diagnoses. Genotyping was done with TaqMan Assay-on-Demand. Analysis was done with the Family Based Association Test program. RESULTS: There were 53 complete, independent trios. The BDNF Val66 allele was preferentially transmitted (Family Based Association Test: chi(2)=6.0, df=1, p=0.014). CONCLUSIONS: This finding in child bipolar disorder is consistent with data for adults with bipolar disorder that show preferential transmission of the Val66 allele.

Adolescent↗
PubMed2003

Effects of prednisone and genetic polymorphisms on etoposide disposition in children with acute lymphoblastic leukemia.

Etoposide is a substrate for P-glycoprotein, CYP3A4, CYP3A5, and UGT1A1. Glucocorticoids modulate CYP3A and P-glycoprotein in preclinical models, but their effect on clinical etoposide disposition is unknown. We studied the pharmacokinetics of etoposide and its catechol metabolite in children with acute lymphoblastic leukemia, along with polymorphisms in CYP3A4, CYP3A5, MDR1, GSTP1, UGT1A1, and VDR. Plasma pharmacokinetics were assessed at day 29, after 1 month of prednisone (n = 102), and at week 54, without prednisone (n = 44). On day 29, etoposide clearance was higher (47.4 versus 29.2 mL/min/m2, P <.0001) than at week 54. The day 29 etoposide or catechol area under the curve (AUC) was correlated with neutropenia (P =.027 and P =.0008, respectively). The relationship between genotype and etoposide disposition differed by race and by prednisone use. The MDR1 exon 26 CC genotype predicted higher day 29 etoposide clearance (P =.002) for all patients, and the CYP3A5 AA and GSTP1 AA genotypes predicted lower clearance in blacks (P =.02 and.03, respectively). The UGT1A1 6/6, VDR intron 8 GG, and VDR Fok 1 CC genotypes predicted higher week 54 clearance in blacks (P =.039,.036, and.052, respectively). The UGT1A1 6/6 genotype predicted lower catechol AUC. Prednisone strongly induces etoposide clearance, genetic polymorphisms may predict the constitutive and induced clearance of etoposide, and the relationship between genotype and phenotype differs by race.

Base Sequence↗
PubMed2003

Homocysteine, pharmacogenetics, and neurotoxicity in children with leukemia.

PURPOSE: Despite its clinical success, methotrexate (MTX) therapy is associated with toxicities such as seizures, the pathogenesis of which remains unclear. It has been suggested that hyperhomocysteinemia is caused by MTX and is responsible for its neurotoxic effects. The purposes of this study were to explore whether hyperhomocysteinemia was related to MTX administration and toxicity and whether homocysteine or MTX toxicity differed by methylenetetrahydrofolate reductase (MTHFR) or reduced folate carrier (RFC) genetic polymorphisms. PATIENTS AND METHODS: We studied 53 children with newly diagnosed acute lymphoblastic leukemia who were consecutively treated on a single clinical protocol that included two courses of high-dose MTX (high-dose methotrexate [HDMTX]; 2.5 or 5.0 g/m2 per day) as consolidation therapy. RESULTS: The study participants' median plasma homocysteine concentrations at 23 and 44 hours after HDMTX (9.00 micromol/L and 10.12 micromol/L, respectively) were greater than the concentrations immediately before HDMTX (5.77 micromol/L, P <.0001 for both comparisons). Seven days after HDMTX treatment, their plasma concentration returned to baseline. Nine patients experienced seizures, and five patients experienced thrombosis during the first 15 months of therapy, with a tendency for there to be higher plasma homocysteine in patients with seizures across all time points (P =.063) but not in patients with thrombosis (P =.59). We observed no significant differences in plasma or cerebrospinal fluid homocysteine levels or in toxicity based on the MTHFR 677C/T or RFC 80G/A genotypes. CONCLUSION: We conclude that homocysteine was transiently elevated after HDMTX and may be related to seizure risk in children with leukemia.

Carrier Proteins↗