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Biomedical subjects

A Bailey

Publications and source records attributed to A Bailey.

At least 73 records · Page 4Linked to original sources

A comparison of sevoflurance to halothane in paediatric surgical patients: results of a multicentre international study.

Induction, emergence and recovery characteristics were compared during sevoflurane or halothane anaesthetic in a large (428) multicentre, international study of children undergoing elective inpatient surgical procedures. Two hundred and fourteen children in each group underwent inhalation induction with nitrous oxide/oxygen and sevoflurane or halothane. Incremental doses of either study drug were added until loss of eyelash reflex was achieved. Steady state concentrations of anaesthesia were maintained until the end of surgery when anaesthetic agents were terminated simultaneously. Time variables were recorded for induction, emergence and the first need for analgesia in the recovery room. In addition, in 86 of the children in both groups, venous blood samples were drawn for plasma fluoride levels during and after surgery. There was a trend toward smoother induction (induction of anaesthesia without coughing, breath holding, excitement laryngospasm, bronchospasm, increased secretion, and vomiting) in the sevoflurane group with faster induction (2.1 min vs 2.9 min, P = 0.037) and rapid emergence times (10.3 min vs 13.9 min, P = 0.003). Among the children given sevoflurane, 2% developed bradycardia compared with 11% in the halothane group. Postoperatively, 46% of the children in the halothane group developed nausea and or vomiting versus 31% in the sevoflurane group (P = 0.002). Two children in the halothane group developed cardiac dysrhythmia and were dropped from the study. In addition, a child in the halothane group developed malignant hyperthermia, received dantrolene, and had an uneventful recovery. Mean maximum inorganic fluoride concentration was 18.3 microM.l-1. The fluoride concentrations peaked within one h of termination of sevoflurane anaesthetic and returned rapidly to baseline within 48 h. This study suggests that sevoflurane may be the drug of choice for the anaesthetic management of children.

Adolescent↗

Autism: towards an integration of clinical, genetic, neuropsychological, and neurobiological perspectives.

Autism constitutes one of the best validated child psychiatric disorders. Empirical research has succeeded in delineating the key clinical phenomena, in demonstrating strong genetic influences on the underlying liability, and in identifying basic cognitive deficits. A range of neurobiological abnormalities has also been found, although the replicability of specific findings has not been high. An understanding of the causal processes leading to autism, and accounting for the marked variability in its manifestations, requires an integration across these different levels of enquiry. Although this is not yet possible, a partial integration provides a useful strategy for identifying key research questions, the limitations of existing hypotheses, and future research directions that are likely to prove fruitful. The research findings for each research level are critically reviewed in order to consider how to move towards an integration across levels.

Adolescent↗

Head circumference in autism and other pervasive developmental disorders.

Recent studies have found that an unexpectedly large proportion of autistic children have large heads. Anthropometric measures of consecutive clinic attenders with pervasive developmental disorder (PDD), other psychiatric or language disorders were analysed. Similar data were obtained from two schools for language disordered children. These data, combined with those from previous studies, indicate that about one-third of children with PDD have macrocephaly based on current percentile charts; this rate was significantly higher than in children with language disorder alone. The finding was not a consequence of recognizable medical disorders and suggests that PDD is sometimes associated with abnormal physical development.

Anthropometry↗

A broader phenotype of autism: the clinical spectrum in twins.

The diagnostic boundaries of the behavioural phenotype for autism were examined in 28 MZ pairs and 20 DZ same-sex twin pairs, where one or both twins had autism. In the non-autistic cotwin (i.e. in twin pairs discordant for autism) it was common to find language impairments in childhood and social deficits persisting into adulthood. Concordance for this broader phenotype was much greater in MZ pairs than DZ pairs, indicating a strong genetic component. Behavioural and cognitive manifestations of autism were compared both within and between MZ twin pairs. The variation was as great within MZ twin pairs as between pairs, suggesting that it does not index genetic heterogeneity (although aetiological heterogeneity probably exists). Current diagnostic practices need re-evaluation.

Activities of Daily Living↗

Why are brain tumours still being missed?

The prediagnosis period of 74 children with primary brain tumours was assessed to examine their presentation and reasons for any delay in diagnosis. Medical case notes were reviewed and parents were interviewed and asked to complete psychological questionnaires. Mean (SD) duration of clinical history was 20.0 (29.1) weeks. Most common symptoms were vomiting (65%) and headache (64%). Only 34% of headaches were always associated with vomiting and only 28% occurred 'early morning'. Changes in the child's personality (47%) were also common. The average number of consultations before diagnosis was 4.6. Migraine was diagnosed in 24% of children and a psychological aetiology in 15%. One quarter of the children had altered levels of consciousness on arrival at the unit. Results indicate that delay in diagnosis still occurs, despite strong parental concern. The nonspecificity of symptoms and a high incidence of psychological symptoms may confound the clinical picture and are considered along with other possible contributory factors.

Adolescent↗

The ACC1 gene, encoding acetyl-CoA carboxylase, is essential for growth in Ustilago maydis.

Acetyl-CoA carboxylase [ACCase; acetyl-CoA:carbon dioxide ligase (ADP forming), EC 6.4.1.2] catalyses the ATP-dependent carboxylation of acetyl-CoA to form malonyl-CoA. We have amplified a fragment of the biotin carboxylase (BC) domain of the Ustilago maydis acetyl-CoA carboxylase (ACC1) gene from genomic DNA and used this amplified DNA fragment as a probe to recover the complete gene from a lambda EMBL3 genomic library. The ACC1 gene has a reading frame of 6555 nucleotides, which is interrupted by a single intron of 80 bp in length. The gene encodes a protein containing 2185 amino acids, with a calculated M(r) of 242,530; this is in good agreement with the size of ACCases from other sources. Further identification was based on the position of putative binding sites for acetyl-CoA, ATP, biotin and carboxybiotin found in other ACCases. A single ACC1 allele was disrupted in a diploid wild-type strain. After sporulation of diploid disruptants, no haploid progeny containing a disrupted acc1 allele were recovered, even though an exogenous source of fatty acids was provided. The data indicate that, in U. maydis, ACCase is required for essential cellular processes other than de novo fatty acid biosynthesis.

Acetyl-CoA Carboxylase↗

Risk of tardive dyskinesia in older patients. A prospective longitudinal study of 266 outpatients.

BACKGROUND: Neuroleptic-induced tardive dyskinesia (TD) is a major iatrogenic disorder that is more prevalent among older patients. The objective of this study was to determine the incidence of and risk factors for TD in neuroleptic-treated patients over age 45 years. METHODS: We studied 266 middle-aged and elderly outpatients with a median duration of 21 days of total lifetime neuroleptic exposure at study entry. Most patients were treated throughout the study with either a high-potency or a low-potency neuroleptic and maintained on relatively low doses. The patients were followed up at 1- to 3-month intervals with "blind" assessment of psychopathologic condition, clinically as well as instrumentally (ie, using electromechanical sensors with computerized data reduction, including spectral analysis) evaluated movement disorder, and global cognitive function. RESULTS: Cumulative incidence of TD was 26%, 52%, and 60% after 1, 2, and 3 years, respectively. The principal risk factors for TD were duration of prior neuroleptic use at baseline, cumulative amount of high-potency neuroleptics, history of alcohol abuse/dependence, borderline or minimal dyskinesia, and tremor on instrumental assessment. CONCLUSION: Use of higher amounts of neuroleptics, particularly high-potency ones, should be avoided in older patients, patients with alcohol abuse/dependence, or patients with a subtle movement disorder at baseline; these patients are at a higher risk of developing TD.

Age Factors↗

A human ubiquitin conjugating enzyme, L-UBC, maps in the Alzheimer's disease locus on chromosome 14q24.3.

We have identified a novel ubiquitin conjugating enzyme gene, L-UBC, which maps to human Chromosome (Chr) 14q24.3. This is also the location of the major early onset familial Alzheimer's disease gene (FAD3). L-UBC encodes a protein that demonstrates homology to the yeast ubiquitin conjugating enzyme, UBC-4, and human UbcH5. Their functions are to ubiquitinate specific proteins targeted for degradation. The protein also exhibits very strong homology to a rabbit protein, E2-F1, which mediates p53 degradation driven by papilloma virus E6 protein in vitro. The accumulation of specific proteins that have undergone aberrant processing in neurofibrillary tangles and amyloid plaques is the classic pathological feature in brains of Alzheimer's disease patients. Abnormal ubiquitination has previously been suggested to play a role in the etiology of Alzheimer's disease. This gene therefore represents a plausible candidate gene for FAD3.

Alzheimer Disease↗

Yeast artificial chromosome cloning of the beta-catenin locus on human chromosome 3p21-22.

beta-Catenin has emerged as an important component of the adherens junctions between epithelial cells. As a result of studies of its interaction with the APC gene product, it has been implicated in the development of colorectal cancer. alpha-Catenin, beta-catenin, E-cadherin and APC appear to mediate contact inhibition in epithelia. As part of the study of the organization of the beta-catenin gene, we have isolated yeast artificial chromosomes (YACs) to characterize its intron/exon structure. YAC fluorescence in situ hybridization analysis and polymerase chain reaction analysis of somatic cell hybrid DNAs show that beta-catenin maps in the 3p21-22 region, the location of tumour-suppressor genes deleted in small-cell lung cancer (SCLC) and other disorders. beta-Catenin YACs will provide a source of microsatellite markers useful in loss of heterozygosity studies to assess the importance of beta-catenin deletions in SCLC.

Base Sequence↗

Autism as a strongly genetic disorder: evidence from a British twin study.

Two previous epidemiological studies of autistic twins suggested that autism was predominantly genetically determined, although the findings with regard to a broader phenotype of cognitive, and possibly social, abnormalities were contradictory. Obstetric and perinatal hazards were also invoked as environmentally determined aetiological factors. The first British twin sample has been re-examined and a second total population sample of autistic twins recruited. In the combined sample 60% of monozygotic (MZ) pairs were concordant for autism versus no dizygotic (DZ) pairs; 92% of MZ pairs were concordant for a broader spectrum of related cognitive or social abnormalities versus 10% of DZ pairs. The findings indicate that autism is under a high degree of genetic control and suggest the involvement of multiple genetic loci. Obstetric hazards usually appear to be consequences of genetically influenced abnormal development, rather than independent aetiological factors. Few new cases had possible medical aetiologies, refuting claims that recognized disorders are common aetiological influences.

Abnormalities, Multiple↗

Prostate-specific membrane antigen: evidence for the existence of a second related human gene.

Prostate-specific membrane antigen (PSM) is a glycoprotein recognised by the prostate-specific monoclonal antibody 7E11-C5, which was raised against the human prostatic carcinoma cell line LNCaP. A cDNA clone for PSM has been described. PSM is of clinical importance for a number of reasons. Radiolabelled antibody is being evaluated both as an imaging agent and as an immunotherapeutic in prostate cancer. Use of the PSM promoter has been advocated for gene therapy applications to drive prostate-specific gene expression. Although PSM is expressed in normal prostate as well as in primary and secondary prostatic carcinoma, different splice variants in malignant tissue afford the prospect of developing reverse transcription-polymerase chain reaction (RT-PCR)-based diagnostic screens for the presence of prostatic carcinoma cells in the circulation. We have undertaken characterisation of the gene for PSM in view of the protein's interesting characteristics. Unexpectedly, we have found that there are other sequences apparently related to PSM in the human genome and that PSM genomic clones map to two separate and distinct loci on human chromosome 11. Investigation of the function of putative PSM-related genes will be necessary to enable us to define fully the role of PSM itself in the development of prostatic carcinoma and in the clinical management of this malignancy.

Antigens, Neoplasm↗

Continuous alteration of the internal milieu of a nerve-guide chamber using an osmotic pump and internal exhaust system.

The use of non-neural conduits to span gaps in regenerating peripheral nerves has been noted in the literature for many years. An intriguing addition to this so-called entubulation repair method is the continuous instillation of neuronotrophic or growth factors into the lumen of the guide to bathe the regenerating nerve. A model is presented which uses an osmotic pump that supplies a constant, reproducible amount of solution into the lumen of a nerve guide without disrupting the regeneration process.

Animals↗

Adherence of Candida albicans to human buccal epithelial cells: host-induced protein synthesis and signaling events.

The synthesis of proteins by Candida albicans was studied following adherence of blastoconidia to human buccal epithelial cells (HBEC). Initially, labeling of HBEC, C. albicans, and HBEC-C. albicans with [35S]methionine was performed. After a 3-h incubation and prior to labeling with [35S]methionine, the cultures were treated with cycloheximide to prevent HBEC protein synthesis. The HBEC-C. albicans mixture as well as C. albicans and HBEC incubated separately were extracted with beta-mercaptoethanol (beta-ME). These extracts as well as the cell residue (solubilized by boiling with sodium dodecyl sulfate [SDS]) were examined by SDS-polyacrylamide gel electrophoresis and autoradiography. In comparison to cultures of C. albicans incubated without HBEC, proteins with molecular masses of approximately 52 to 56 kDa from beta-ME extracts and from SDS-solubilized cells were observed only from adhering cultures. In addition, unlabeled beta-ME extracts were electrotransferred to nitrocellulose and immunoblotted with antiphosphotyrosine antibodies to determine whether cell signaling events were occurring during adherence. Proteins with molecular masses of 54 and 60 kDa were recognized only in mixed cultures of C. albicans and HBEC. These data indicate that following adherence of C. albicans to HBEC, new Candida proteins are expressed. Further, these events are accompanied by the expression of signal proteins, presumably of Candida origin.

Candida albicans↗

Childhood lead poisoning in Massachusetts communities: its association with sociodemographic and housing characteristics.

OBJECTIVES: The purpose of the study was to examine the relationship between communities' sociodemographic and housing characteristics and incidence of lead poisoning. METHODS: This was a population-based correlational study of 238,275 Massachusetts children from birth through 4 years of age who were screened for lead poisoning in 1991-1992. A logistic regression model was developed with the community as the unit of analysis, the case identification rate for lead poisoning (newly identified children with venous blood lead > or = 25 micrograms/dL per 1000 children) as the dependent variable, and US census variables as independent variables. RESULTS: A significant independent relationship with the community case identification rate of lead poisoning was found for seven variables: median per capita income, percentage of housing built before 1950, percentage of the population who were Black, percentage of children screened, and a "poverty index." Rates of iron deficiency and percentage of Hispanics were not associated with the case identification rate of lead poisoning. CONCLUSIONS: Massachusetts communities' incidence of lead poisoning is correlated with sociodemographic and housing characteristics. In states similar to Massachusetts and without screening data, this model may help target screening programs.

Black or African American↗

Latent-class analysis of recurrence risks for complex phenotypes with selection and measurement error: a twin and family history study of autism.

The use of the family history method to examine the pattern of recurrence risks for complex disorders such as autism is not straightforward. Problems such as uncertain phenotypic definition, unreliable measurement with increased error rates for more distant relatives, and selection due to reduced fertility all complicate the estimation of risk ratios. Using data from a recent family history study of autism, and a similar study of twins, this paper shows how a latent-class approach can be used to tackle these problems. New findings are presented supporting a multiple-locus model of inheritance, with three loci giving the best fit.

Autistic Disorder↗