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Biomedical subjects

M A Roberts

Publications and source records attributed to M A Roberts.

At least 37 records · Page 2Linked to original sources
PubMed1999

Cognitive outcome in children and adolescents following severe traumatic brain injury: influence of psychosocial, psychiatric, and injury-related variables.

Previous studies of childhood traumatic brain injury (TBI) have emphasized injury-related variables rather than psychiatric or psychosocial factors as correlates of cognitive outcomes. We addressed this concern by recruiting a consecutive series (N = 24) of children age 5 through 14 years who suffered a severe TBI, a matched group who sustained a mild TBI, and a second matched group who sustained an orthopedic injury. Standardized intellectual, memory, psychiatric, family functioning, family psychiatric history, neurological, and neuroimaging assessments were conducted at an average of 2 years following injury. Severe TBI, when compared to mild TBI and orthopedic injury, was associated with significant decrements in intellectual and memory function. A principal components analysis of independent variables that showed significant (p < .05) bivariate correlations with the outcome measures yielded a neuropsychiatric factor encompassing severity of TBI indices and postinjury psychiatric disorders and a psychosocial disadvantage factor. Both factors were independently and significantly related to intellectual and memory function outcome. Postinjury psychiatric disorders added significantly to severity indices and family functioning and family psychiatric history added significantly to socioeconomic status in explaining several specific cognitive outcomes. These results may help to define subgroups of children who will require more intensive services following their injuries.

Adolescent↗
PubMed1999

Serological response to influenza vaccination and nutritional and functional status of patients in geriatric medical long-term care.

INTRODUCTION: in the UK the Department of Health recommends influenza vaccination for elderly people resident in institutional care. However, the efficacy of vaccination may be reduced in very frail elderly people with functional impairment, undernutrition and multiple pathologies. Nutritional and functional status is claimed to affect vaccine responses in healthy elderly subjects. We wished to determine if a relationship could be seen between nutritional and functional status and seroconversion in patients receiving long- term care. METHODS: all patients in geriatric medical long-term care were offered vaccine. Consenting patients had pre- and post-vaccine serology measured using single radial haemolysis. Anthropometry was measured to enable body mass index (BMI) to be calculated. Functional independence was assessed using the 20-point Barthel index. RESULTS: of 260 patients who received influenza vaccine, 137 (36 male, 101 female) consented to venesection for serology and thus form the study population. Mean age was 82 years (SD 7.9). The median Barthel score was 3/20 and the mean BMI was 21.6 (SD 4.6, range 13-36.2). Antibodies to influenza A were undetectable both pre- and post-vaccination in 63/137 patients. In 49 patients the antibody titre rose after vaccination and 25 had detectable antibody titres pre-vaccination which failed to rise post-vaccine. There were no significant associations between post-vaccination influenza antibody responses and BMI, Barthel score or age. CONCLUSION: frail elderly patients in geriatric medical long-term care had a poor antibody response to influenza vaccination. Within this group, serological responses could not be predicted by nutritional or functional status.

Aged↗
PubMed1999

Induction and characterization of Ph1 wheat mutants.

The cloning of genes for complex traits in polyploid plants that possess large genomes, such as hexaploid wheat, requires an efficient strategy. We present here one such strategy focusing on the homologous pairing suppressor (Ph1) locus of wheat. This locus has been shown to affect both premeiotic and meiotic processes, possibly suggesting a complex control. The strategy combined the identification of lines carrying specific deletions using multiplex PCR screening of fast-neutron irradiated wheat populations with the approach of physically mapping the region in the rice genome equivalent to the deletion to reveal its gene content. As a result, we have located the Ph1 factor controlling the euploid-like level of homologous chromosome pairing to the region between two loci (Xrgc846 and Xpsr150A). These loci are located within 400 kb of each other in the rice genome. By sequencing this region of the rice genome, it should now be possible to define the nature of this factor.

Base Sequence↗
PubMed1999

The epidemiology of women's rugby injuries.

OBJECTIVE: The purpose of this study was to identify all injuries to members of an elite women's rugby team and to compare these injuries with published data on injuries in other women's contact and collision sports. DESIGN: This was a prospective cohort observational study conducted using a monthly log completed by the team's certified athletic therapist to closely monitor attendance at practices and games along with the type and severity of injuries. SETTING: Rugby games and practices held in Ontario, Quebec, and the Netherlands. PARTICIPANTS: Forty members of the Ontario Women's Senior Provincial Rugby Team over the 1997 season and the 1998 World Championships. MAIN OUTCOME MEASURES: An injury was defined as a rugby-related event that kept a player out of practice or competition for >24 hours or required the attention of a physician (e.g., suturing lacerations) and in addition included all dental, eye, and nerve injuries and concussions. RESULTS: There were a total of 35 injuries in 4,958 player-hours and 2,926 athletic exposures. This resulted in a rugby injury rate of 7.1+/-0.4 per 1,000 player-hours and 12.0+/-2 per 1,000 athletic exposures. CONCLUSION: The incidence of injuries in women's rugby is comparable with that in other women's contact and collision sports, indicating that the sport may be safer than stated in the literature and media.

Adolescent↗
PubMed1998

Angular resolution of parallel foils on a synchrotron powder diffractometer.

In an attempt to improve the resolution in flat-plate diffraction geometry, a new set of parallel foils, 100 microm spacing, 365 mm long with an aperture of 20 x 20 mm(2), has been commissioned. The study was carried out using the two-circle diffractometer of station 2.3 at the SRS. In order to properly quantify the improvements, a detailed and comparative study of the instrumental resolution using the new and existing foils, of 200 micron spacing, is reported. A number of cubic materials, BaF2, Si and CeO2, that are known to show well defined Bragg peaks over the full 2theta angular range available, were investigated.

Journal Article↗
PubMed1998

Redefining reductive sulfate assimilation in higher plants: a role for APS reductase, a new member of the thioredoxin superfamily?

The reaction steps leading from the intermediate adenosine 5'-phosphosulfate (APS) to sulfide within the higher plant reductive sulfate assimilation pathway are the subject of controversy. Two pathways have been proposed: a 'bound intermediate' pathway in which the sulfo group of APS is first transferred by APS sulfotransferase to a carrier molecule to form a bound sulfite intermediate and is then further reduced by thiosulfonate reductase to bound sulfide; and a 'free intermediate' pathway in which APS is further activated to 3'-phosphoadenosine 5'-phosphosulfate (PAPS) by APS kinase followed by reduction of the sulfo group to free sulfite by PAPS reductase. Sulfite is then reduced to free sulfide by sulfite reductase. Sulfide, either free or bound, is then incorporated into organic form (as cysteine) by the enzyme O-acetylserine (thiol) lyase. In order to better characterize the pathway we attempted to clone PAPS reductase cDNAs by functional complementation of an Escherichia coli cysH mutant to prototrophy. We found no evidence for PAPS reductase cDNAs but did identify cDNAs that encode a small family of novel, chloroplast-localized proteins with APS reductase activity that are new members of the thioredoxin superfamily. We show here that the thioredoxin domain of these proteins is functional. We speculate that rather than proceeding via either of the pathways proposed above, reductive sulfate assimilation proceeds via the reduction of APS to sulfite by APS reductase and the subsequent reduction of sulfite to sulfide by sulfite reductase. In this scheme the product of the APS kinase reaction, PAPS, is not a direct intermediate in the pathway but rather acts as a substrate for sulfotransferase action and perhaps as a store of activated sulfate that can be returned to the pathway as APS via phosphohydrolase action on PAPS. Interactions between enzyme isoforms within the chloroplast stroma may bring about substrate channeling of APS and contribute to the partitioning of APS between sulfotransferase reactions on the one hand and the synthesis of cysteine and related metabolites via the reductive sulfate assimilation pathway on the other.

Oxidation-Reduction↗
PubMed1998

Small-scale isolation of genomic DNA from Streptomyces mycelia or spores.

We have developed a small-scale method for isolating high-quality chromosomal DNA from Streptomyces species. The entire procedure may be carried out in 2-mL microcentrifuge tubes in one day. It has been tested both quantitatively and qualitatively to ensure reliability and reproducibility. DNA yields from a variety of Streptomyces species ranged from 30 micrograms DNA/50 mg cells to over 225 micrograms DNA/50 mg cells. We used the method to isolate DNA from cells grown in liquid culture, on solid media and from spore suspensions. DNA yields and quality were assessed by spectrophotometry, restriction endonuclease digestion and random-amplified polymorphic DNA-PCR (RAPD-PCR) analysis. These confirmed that this procedure is an efficient method for isolating large amounts of high-quality DNA from a wide range of Streptomyces species.

Culture Media↗
PubMed1997

Senior house officers in medicine: postal survey of training and work experience.

OBJECTIVES: To describe working conditions for senior house officers in medicine in Scotland and to relate these to the quality of clinical training they receive. DESIGN: Postal questionnaire survey. SUBJECTS: All senior house officers in medicine and related specialties in post in Scotland in October 1995 (n = 437); 252 (58%) respondents. MAIN OUTCOME MEASURES: Questionnaires covered hours, working patterns, measures of workload, an attitudes to work scale, and experience of education and training. RESULTS: In the week before the questionnaire, doctors on rotas had worked a mean of 7.4 (95% confidence interval 5.8 to 9.0) hours in excess of their contracts, compared with 3.7 (2.0 to 5.5) hours for those on partial shifts. The most common reason for this was "the needs of the patients or the service." Those on partial shifts reported significantly less continuity of care with patients than those on rotas (Mann-Whitney U test, z = -4.2, P < 0.0001) or full shifts (z = -2.08, P = 0.03). Doctors in general medicine reported significantly higher measures of workload (number of acute admissions, number of times called out, and fewest hours' uninterrupted sleep) than those in subspecialties. Consultants' clinical teaching and style of conducting a ward round were significantly related to factors extracted from the attitudes to work scale. CONCLUSIONS: The quality of senior house officers' training is detrimentally affected by a variety of conditions, especially the need for closer support and supervision, the need for greater feedback, and the lack of time that consultants have to dedicate to clinical training. Efforts should be made to improve these conditions and to reinforce a close working relationship between trainee and supervising consultant.

Adaptation, Psychological↗
PubMed1997

Cysteine biosynthesis in higher plants: a new member of the Arabidopsis thaliana serine acetyltransferase small gene-family obtained by functional complementation of an Escherichia coli cysteine auxotroph.

A cDNA clone, Sat-52, encoding a novel isoform of serine acetyltransferase (EC 2.3.1.30) was isolated by functional complementation of an Escherichia coli cysE mutant defective in serine acetyltransferase. The 1158 base pair clone contains a full-length open reading frame encoding a deduced protein of 312 amino acids with an M(r) of 32.77 kDa. Northern analysis revealed a single transcript of ca 1.19 kb that did not increase in abundance under sulfate limitation. Genomic Southern hybridization suggests the presence of a single copy of the Sat-52 gene.

Acetyltransferases↗
PubMed1997

Associations between clinic-referred boys and their fathers on childhood inattention-overactivity and aggression dimensions.

The question asked in this study of 70 clinically referred 6- to 12-year-old boys with behavior problems was whether or not childhood inattention-overactivity and aggression are transmitted specifically from biological fathers to sons. Fathers' self-reported childhood inattention-overactivity on a retrospectively valid measure was exclusively associated with parents' ratings of their sons' current attention problems on the Mothers' Operational Measure for Subgrouping (MOMS), the Revised Child Behavior Checklist (RCBCL), and an approximated DSM-IV inattention dimension. Fathers' self-reported childhood aggression was not associated with ratings of their sons' aggression on the MOMS or DADS (a parallel instrument for fathers), nor on DSM-III oppositional or conduct disorder dimensions, but it was exclusively associated with RCBCL ratings of sons' aggressive and delinquent behavior. None of the nonspecific correlations (father inattention-overactivity with son aggression or father aggression with son inattention-overactivity) was significant.

Aggression↗
PubMed1997

Influenza vaccination of health care workers in long-term-care hospitals reduces the mortality of elderly patients.

Vaccination of health care workers (HCWs) is recommended as a strategy for preventing influenza in elderly patients in long-term care. However, there have been no controlled studies to show whether this approach is effective. During the winter of 1994-1995, 1059 patients in 12 geriatric medical long-term-care sites, randomized for vaccination of HCWs, were studied. In hospitals where HCWs were offered vaccination, 653 (61%) of 1078 were vaccinated. Vaccination of HCWs was associated with reductions in total patient mortality from 17% to 10% (odds ratio [OR], 0.56; 95% confidence interval [CI], 0.40-0.80) and in influenza-like illness (OR, 0.57; 95% CI, 0.34-0.94). Vaccination of patients was not associated with significant effects on mortality (OR, 1.15; 95% CI, 0.81-1.64). Results of this study support recommendations for vaccination against influenza of HCWs in long-term geriatric care. Vaccination of frail elderly long-term-care patients may not give clinically worthwhile benefits.

Aged↗
PubMed1997

Eliciting parental report following pediatric traumatic brain injury: preliminary findings on the Pediatric Inventory of Neurobehavioral Symptoms.

The current article presents preliminary normative data for the Pediatric Inventory of Neurobehavioral Symptoms (PINS), a parent rating scale consisting of symptoms associated with post-traumatic cerebral dysfunction, such as disinhibition, perseveration, reduced spontaneity, inappropriate affective responses, episodic phenomena, and disruptions of biologic function. Comparison data from a sample of 50 elementary age children who had sustained traumatic brain injury (TBI) reveals significant differences on the PINS total score and each of five subscale scores. Two of the 5 PINS subscales (Episodic Symptoms, Biologic Signs) significantly differentiated the TBI and Attention Deficit Hyperactivity Disorder (n = 35) groups, suggesting that these may be clinical features that distinguish post-traumatic cerebral dysfunction from developmental psychopathology. Despite the need for additional research, the PINS appears to be a promising new measure in advancing our understanding of the neurobehavioral sequelae of pediatric traumatic brain injury.

Journal Article↗
PubMed1996

Three members of a novel small gene-family from Arabidopsis thaliana able to complement functionally an Escherichia coli mutant defective in PAPS reductase activity encode proteins with a thioredoxin-like domain and "APS reductase" activity.

Three different cDNAs, Prh-19, Prh-26, and Prh-43 [3'-phosphoadenosine-5'-phosphosulfate (PAPS) reductase homolog], have been isolated by complementation of an Escherichia coli cysH mutant, defective in PAPS reductase activity, to prototrophy with an Arabidopsis thaliana cDNA library in the expression vector lambda YES. Sequence analysis of the cDNAs revealed continuous open reading frames encoding polypeptides of 465, 458, and 453 amino acids, with calculated molecular masses of 51.3, 50.5, and 50.4 kDa, respectively, that have strong homology with fungal, yeast and bacterial PAPS reductases. However, unlike microbial PAPS reductases, each PRH protein has an N-terminal extension, characteristic of a plastid transit peptide, and a C-terminal extension that has amino acid and deduced three-dimensional homology to thioredoxin proteins. Adenosine 5'-phosphosulfate (APS) was shown to be a much more efficient substrate than PAPS when the activity of the PRH proteins was tested by their ability to convert 35S-labeled substrate to acid-volatile 35S-sulfite. We speculate that the thioredoxin-like domain is involved in catalytic function, and that the PRH proteins may function as novel "APS reductase" enzymes. Southern hybridization analysis showed the presence of a small multigene family in the Arabidopsis genome. RNA blot hybridization with gene-specific probes revealed for each gene the presence of a transcript of approximately 1.85 kb in leaves, stems, and roots that increased on sulfate starvation. To our knowledge, this is the first report of the cloning and characterization of plant genes that encode proteins with APS reductase activity and supports the suggestion that APS can be utilized directly, without activation to PAPS, as an intermediary substrate in reductive sulfate assimilation.

Amino Acid Sequence↗
PubMed1996

Cloning and characterization of an Arabidopsis thaliana cDNA clone encoding an organellar isoform of serine acetyltransferase.

We have cloned an Arabidopsis thaliana cDNA encoding serine acetyltransferase (EC 2.3.1.30) by functional complementation of the Escherichia coli cysE mutant JM15. The cDNA clone Sat-1 conferred serine acetyltransferase activity (with apparent Km for the two substrates acetyl CoA and L-serine of 0.043 and 3.47 mmol/dm3 respectively) on the cysE mutant. The 1515 bp full-length cDNA encodes a deduced protein of 391 amino acids which includes a putative chloroplastic targeting presequence. Northern analysis revealed a single message of 1.5 kb, while Southern hybridisation suggests a small multigene family of related sequences.

Acetyltransferases↗
PubMed1996

Episodic symptoms in dysfunctioning children and adolescents following mild and severe traumatic brain injury.

The present investigation examines the phenomenology of episodic symptoms in dysfunctioning children and adolescents following mild (n = 25) or severe (n = 25) traumatic brain injury (TBI). TBI patients in both groups commonly endorsed symptoms such as staring spells, memory gaps, and temper outbursts. Anticonvulsant response in the 27 patients treated, reflected moderate to substantial improvement in 92%. A dose-response relationship between injury severity and number of episodic symptoms was not observed; however, patients in the severe TBI sample did produce significantly more defective performances on a dichotic word-listening task (DWLT) and lower IQ values. Defective DWLT performance was also significantly associated with greater number of episodic symptoms endorsed, but only in the mild TBI sample. Parallels with epilepsy spectrum disorder and clinical implications for paediatric TBI are discussed.

Adolescent↗
PubMed1996

Human cloning: a case of no harm done?

Some have objected to the laboratory cloning of human preembryos on the grounds that the procedure would violate the dignity of and respect owed to human preembryos. Others have argued that human cloning ought be permitted if it will predictably benefit, or at least not burden, individuals who are, unlike the human preembryo, clearly entitled to our respect and concern. Taking this latter position, the legal theorist John A. Robertson has argued that, since cloning does not harm anyone who is clearly entitled to our respect and concern, it should be permitted. In particular, the offspring of cloning, he argues, cannot be genuinely harmed by cloning, since they owe their very existence to the cloning procedure. In this paper, I argue that cloning coupled with its related procedures does in fact place the flesh and blood human offspring of cloning at risk of genuine harm. I thus provide a basis for questioning the moral permissibility of cloning and its related technologies without implying that the human preembryo has dignity or is owed respect.

Bioethics↗