Search PubMed⌕ Search

Biomedical subjects

Michael Fitzgerald

Publications and source records attributed to Michael Fitzgerald.

At least 19 recordsLinked to original sources
PubMed2004

Synthesis and structure-activity relationships of a novel series of 2,3,5,6,7,9-hexahydrothieno[3,2-b]quinolin-8(4H)-one 1,1-dioxide K(ATP) channel openers: discovery of (-)-(9S)-9-(3-bromo-4-fluorophenyl)-2,3,5,6,7,9- hexahydrothieno[3,2-b]quinolin-8(4H)-one 1,1-dioxide (A-278637), a potent K(ATP) opener that selectively inhibits spontaneous bladder contractions.

Structure-activity relationships were investigated on a novel series of sulfonyldihydropyridine-containing K(ATP) openers. Ring sizes, absolute stereochemistry, and aromatic substitution were evaluated for K(ATP) activity in guinea pig bladder cells using a fluorescence-based membrane potential assay and in a pig bladder strip assay. The inhibition of spontaneous bladder contractions in vitro was also examined for a select group of compounds. All compounds studied showed greater potency to inhibit spontaneous bladder contractions relative to their potencies to inhibit contractions elicited by electrical stimulation. In an anesthetized pig model of myogenic bladder overactivity, compound 14 and (-)-cromakalim 1 were found to inhibit spontaneous bladder contractions in vivo at plasma concentrations lower than those that affected hemodynamic parameters. Compound 14 showed approximately 5-fold greater selectivity than 1 in vivo and supports the concept that bladder-selective K(ATP) channel openers may have utility in the treatment of overactive bladder.

Adenosine Triphosphate↗
PubMed2004

An efficient multigram synthesis of the potent histamine H3 antagonist GT-2331 and the reassessment of the absolute configuration.

GT-2331 is a potent histamine H(3) antagonist which has entered clinical trials. Efficient multigram syntheses of this compound and its enantiomer are described. The literature reports that GT-2331 is the dextrorotatory (+), more potent, enantiomer of 4-[2-(5,5-dimethylhex-1-ynyl)cyclopropyl]-1H-imidazole with the absolute configuration of (1R,2R)-1. However, we found that the dextrorotatory, more potent, enantiomer of 4-[2-(5,5-dimethylhex-1-ynyl)cyclopropyl]-1H-imidazole has the (1S,2S) absolute configuration. We suggest a reconsideration of the absolute configuration of GT-2331.

Crystallography, X-Ray↗
PubMed2004

No association between allelic variants of HOXA1/HOXB1 and autism.

Two recent studies have reported conflicting findings of association of a variant in the HOXA1 gene and autism. To try to resolve the conflict in findings, we conducted an association study in 78 Irish families of the reported DNA variants. We did not find statistically significant association between the variants and autism. Similarly there was no evidence of preferential transmission of variants from parent of either sex to affected offspring. We also report negative findings for HOXB1 variants. We conclude that the HOXA1/B1 are unlikely to be the susceptibility genes for autism in our sample.

Alleles↗
PubMed2004

Did Michelangelo (1475-1564) have high-functioning autism?

In this paper evidence is presented that Michelangelo met the criteria for Asperger's disorder, or high-functioning autism. The evidence relates to his single-minded work routine, unusual lifestyle, limited interests, poor social and communication skills, and issues of life control. Depression and various medical conditions, including gout, renal colic and renal stones, did not stop his obsessive working habits.

Art↗
PubMed2003

Association of the 480 bp DAT1 allele with methylphenidate response in a sample of Irish children with ADHD.

Several studies have implicated the dopamine transporter gene (DAT1) as conferring susceptibility to attention deficit hyperactivity disorder (ADHD), in particular, a VNTR situated at the 3' end of the gene. In addition, the 10-repeat VNTR allele associated with ADHD has been reported to be associated with an over-active transporter protein (DAT). Thus children possessing this variant might be particularly responsive to methylphenidate, a drug known to act by blocking DAT. We have examined this hypothesis and now report an association between the 10-repeat VNTR DAT1 polymorphism and retrospectively rated methylphenidate response in a sample of 119 Irish children with ADHD (chi(2) = 7.918, df = 1, P = 0.005). Our findings suggest a role for the 10-repeat DAT1 risk allele in medication response and may help to predict positive clinical outcome in ADHD.

Attention Deficit Disorder with Hyperactivity↗
PubMed2003

Plasma amino acid levels in children with autism and their families.

Plasma amino acid levels were measured in autistic and Asperger syndrome patients, their siblings, and parents. The results were compared with values from age-matched controls. Patients with autism or Asperger syndrome and their siblings and parents all had raised glutamic acid, phenylalanine, asparagine, tyrosine, alanine, and lysine (p < .05) than controls, with reduced plasma glutamine. Other amino acids were at normal levels. These results show that children with autistic spectrum disorders come from a family background of dysregulated amino acid metabolism and provide further evidence for an underlying biochemical basis for the condition.

Adolescent↗
PubMed2003

Brief report: A case of autism associated with del(2)(q32.1q32.2) or (q32.2q32.3).

Autism is a neurodevelopmental disorder presenting in the first 3 years of life. Deficits occur in the three core areas of communication, social interaction, and behavior. The causes of autism are unknown, but clinical genetic studies show strong evidence in favor of a genetic etiology. Molecular genetic studies report some association with candidate genes, and candidate regions have emerged from several genome-wide linkage studies. Here we report a clinical case of autism with a deletion on chromosome 2 in a young male with high-functioning autism. The deletion seems to correspond with regions emerging from linkage studies. We propose this as a possible candidate region in the search for autism genes.

Adolescent↗
PubMed2002

Association of DRD4 in children with ADHD and comorbid conduct problems.

Recent family and twin study findings suggest that ADHD when comorbid with conduct problems may represent a particularly familial and heritable form of ADHD. Although several independent groups have shown association between the DRD4 7 repeat allele and ADHD, others have failed to replicate this finding. Previous TDT analyses of UK and Eire samples had also been negative. We set out to further examine the role of DRD4 but selecting a subgroup of children with ADHD and comorbid conduct problems. Families were recruited from Manchester, Ireland, Birmingham and London clinics. From these, 67 children who fulfilled diagnostic criteria for ADHD and who displayed conduct disorder symptoms were selected. TDT analysis, which had previously yielded negative results for the total sample, showed evidence of association between DRD4 and "ADHD with conduct problems" (7 repeat allele-24 transmissions, 13 non-transmissions; one-tailed P=0.05). These results provide further support for the role of DRD4 in ADHD. Furthermore, these results when considered together with family and twin study findings, suggest that those children with ADHD and comorbid conduct problems may be particularly informative for molecular genetic studies of ADHD. Further work is needed to examine these phenotype issues.

Adolescent↗
PubMed2002

Synthesis and biological evaluation of 2-indolyloxazolines as a new class of tubulin polymerization inhibitors. Discovery of A-289099 as an orally active antitumor agent.

A series of indole containing oxazolines has been discovered as a result of structural modifications of the lead compound A-105972. The compounds exert their anticancer activity through inhibition of tubulin polymerization by binding at the colchicine site. A-289099 was identified as an orally active antimitotic agent active against various cancer cell lines including those that express the MDR phenotype. The anticancer activity, pharmacokinetics, and an efficient and enantioselective synthesis of A-289099 are described.

Animals↗
PubMed2002

Symptom domains in autism and related conditions: evidence for familiality.

Heterogeneity in autism impairs efforts to localize and identify the genes underlying this disorder. As autism comprises severe but variable deficits and traits in three symptom domains (social interaction, communication, and repetitive behaviors) and shows variability in the presence and emergence of useful phrase speech, different genetic factors may be associated with each. The affected cases (n=457) in multiply affected siblingships (n=212), including a proband with autism and one or more siblings with either autism or marked deficits in autism symptom domains, were assessed using the Autism Diagnostic Interview, Revised. Symptom domain scores and language features were examined to determine their similarity within siblingships. The variance within siblingships was reduced for the repetitive behavior domain and for delays in and the presence of useful phrase speech. These features and the nonverbal communication subdomain provided evidence of familiality when we considered only the diagnosis of autism to define multiply affected siblingships (cases: n=289; siblingships: n=136). In addition, the same familial features identified also appeared familial for those with autism-related conditions. Finally, the level of severity of almost all of the familial features varied within multiplex siblingships independently. The features identified as familial replicate the combined set suggested in earlier, smaller studies. Furthermore, the familiality of these features extend to related conditions of milder severity than autism and appear to be independent. Making distinctions among families by the severity of these features may be useful for identifying more genetically homogeneous subgroups in studies targeted at genes for specific autism-related symptom domains.

Autistic Disorder↗
PubMed2002

Dopaminergic system genes in ADHD: toward a biological hypothesis.

Converging evidence has implicated abnormalities of dopamine neurotransmission to the pathology of attention deficit hyperactivity disorder (ADHD). Several genetic association studies have been published, but so far, no DNA variants have been unequivocally demonstrated as contributing to ADHD susceptibility. Four dopamine related gene loci have been implicated, however: DAT 1, DRD 4, DBH, and DRD 5. Each of these may influence the liability of ADHD to a small degree. Notably, all are involved in signal transduction at the neuronal synapse. In this article, we investigate as candidate genes for ADHD, DNA polymorphisms at dopamine receptors, the dopamine transporter, and genes known to be involved in dopamine synthesis and metabolism. In a recent article, we confirmed the previously reported association of DAT 1 (480 bp allele) with ADHD and identified polymorphisms at two additional loci showing preferential transmission to ADHD children of alleles at DRD 5 (148 bp allele) and at DBH (allele 2, Taq I polymorphism). Increased transmission of the 4 bp deletion in the untranslated exon 1 of the DOPA decarboxylase gene was also observed but was of marginal significance. Nonsignificant trends of association were found for TH (allele 2) and DRD2 (Ser-311). No preferential transmission of alleles to ADHD children was observed for polymorphisms at DRD 1, DRD 2 (Taq I), DRD 3, DRD 4, and COMT. Analyzing the data by sex of transmitting parent showed significant preferential paternal transmission of alleles at TH (allele 2) and a nonsignificant trend for paternal transmission for DRD 2 (Ser-311). We attempt to put these findings together with what is known of the function of the particular proteins, and suggest working hypotheses.

Adolescent↗
PubMed2002

European adolescent substance use: the roles of family structure, function and gender.

OBJECTIVES: The aim of this study was, first, to explore family structure and measures of family functioning in relation to adolescent substance use and secondly, to establish if these relationships differed according to gender or according to the city of origin of the sample. DESIGN, SETTING, PARTICIPANTS: The study surveyed pupils aged 14-15 years in representative samples drawn from five European cities: Newcastle upon Tyne, Dublin, Rome, Bremen and Groningen. Data were obtained on 3984 participants in relation to their substance use, living with both biological parents, confiding in parents and grandparents. and supervision, as well as other variables representing delinquency, social class and drug availability. RESULTS: Living with both parents was associated with reduced levels of drug use in four cities but not in Dublin, due perhaps to the high availability from peers in that city. It was not associated with reduced levels of regular drinking. The effect of confiding in mother was evident in all cities and in relation to substance use in general. However, when a delinquency variable was added to the logistic regressions, its significance in relation to polydrug use disappeared. Supervision was somewhat more important in relation to male than female drug use. CONCLUSION: Living with both parents is a less robust barrier to substance use than qualitative aspects of family life, particularly attachment to mothers. The latter is a robust inhibitor of substance use irrespective of regional differences in drug availability, weakening only in the face of more generally problematic behaviour. Perhaps because of their greater tendency to risk-taking or rule breaking, supervision appears more important for male than female drug use. These findings underscore the role of families, but especially that of mothers, in regulating the substance-related behaviour of young people.

Adolescent↗