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Biomedical subjects

J Wood

Publications and source records attributed to J Wood.

At least 109 records · Page 6Linked to original sources
PubMed1999

The new subnational population projections model: methodology and projection scenarios.

This article describes the most recent process of projecting population at the subnational level in England. It briefly explains the reasons why projecting population at the subnational level is important, describes the model and how it was used to produce the latest set of long-term subnational population projections in England published by the Office for National Statistics (ONS) in 1998. The article then discusses how the model may be applied to answer various 'what-if' questions about future population.

Adolescent↗
PubMed1999

Will stentless valves be durable? The Toronto valve (TSPV) at 5 to 6 years.

The early hemodynamic benefits of stentless aortic valves have been well documented. The issue of long-term functional integrity remains unanswered. We report the clinical results of a multicenter registry with prospective data on 621 patients monitored for 7.1 years. Patient data were collected and analyzed at St Jude Medical Inc, St Paul, Minnesota. In all, 66% of patients were male; the average age was 65.9 years +/-11.0 years, with 39% older than 70 years. Native aortic valves were bicuspid in 40.6%, 91.5% were calcified and 65.7% stenotic. Most valves implanted (83.1%) were sizes 25, 27, or 29 mm. Concomitant coronary bypass was performed in 42% of patients. Total follow-up time for the 621 patients was 1,944.5 valve years (mean 3.1 years per patient). At 5 years, 86.1% (n = 137) and at 6 years 80.4% (n = 51) were in New York Heart Association class I, and 78% had no or trivial atrial insufficiency. The average mean systolic gradient for all valves at 6 years was 4.0 mm Hg, and the peak gradient was 8.6 mm Hg. The effective orifice area varied from 1.4 cm2 (23-mm valve) to 2.7 cm2 (29-mm valve). The decrease in left ventricular mass index was significant and sustained. Actuarial survival at 6 years was 84.2%, and freedom from cardiac-related deaths was 90.1%. Freedom from valve-related deaths was 95.7%, and freedom from prosthetic endocarditis was 98.6%. There were no instances of primary tissue valve failure during follow-up, with 97.2% freedom from reoperation. The early hemodynamic benefits of the TSPV are well maintained during more than 6 years of follow-up, without evident valvular dysfunction. Longer follow-up time is required to validate durability, but there is increasing evidence for well-maintained structural and functional integrity.

Actuarial Analysis↗
PubMed1999

Psychological changes in hundred-day remote Antarctic field groups.

Psychological adaptation to extreme environments has been examined from several perspectives. In this study, two Australian teams, each consisting of six male crew members, completed computer-administered questionnaires twice weekly during 100-day traverses around the Lambert Glacier Basin, Antarctica. Only small trends were noted when data were aggregated at the group level, which is consistent with the findings of others. Data were then analyzed using pooled time-series regression. These analyses incorporated personality characteristics, environmental factors, and interpersonal factors as predictors of Group Tensions, Personal Morale, Emotional State, Cognitive Readiness, and the Team's Work Life. Most of the psychological discomfort and problems that occurred appeared to be within the individual or between individuals. They did not affect all members of the group equally.

Adaptation, Psychological↗
PubMed1998

Hemodynamics and left ventricular mass regression following implantation of the Toronto SPV stentless porcine valve.

Stentless tissue valves may provide more favorable hemodynamics than conventional stented valves. Hemodynamic findings from a large multicenter trial have not been previously reported. The present report describes the hemodynamic findings from a multinational, multicenter study after implantation of the Toronto SPV valve. A total of 577 patients underwent aortic valve replacement with the Toronto SPV valve at 12 sites in 3 countries. Echocardiograms were recorded in the early postoperative period, 3 to 6 months after surgery, 1 year after surgery, and yearly thereafter, with follow-up to 3 years. Gradients decreased and effective orifice area increased in the months after surgery. One year after surgery, mean gradient for valve sizes 20 to 22, 23, 25, 27, and 29 mm was 7.3 +/- 4.4, 7.4 +/- 4.5, 6.1 +/- 3.3, 4.9 +/- 2.4, and 4.0 +/- 2.1 mm Hg, respectively; effective orifice area was 1.3 +/- 0.7, 1.5 +/- 0.5, 1.7 +/- 0.4, 2.0 +/- 0.4, and 2.4 +/- 0.6 cm2, respectively. There was a very low prevalence of significant aortic regurgitation at all time periods. There was significant left ventricular (LV) mass regression between the early and 3- to 6-month periods and between the 3- to 6-month and 1-year postoperative periods. The Toronto SPV valve has an excellent hemodynamic profile supported by significant regression of LV hypertrophy in the year after implantation. Data through 3 years demonstrates maintenance of low gradients and freedom from significant aortic regurgitation.

Aged↗
PubMed1998

Active versus expectant management of third stage of labour: the Hinchingbrooke randomised controlled trial.

BACKGROUND: This study tested the hypotheses that active management of the third stage of labour lowers the rates of primary postpartum haemorrhage (PPH) and longer-term consequences compared with expectant management, in a setting where both managements are commonly practised, and that this effect is not mediated by maternal posture. BACKGROUND: 1512 women judged to be at low risk of PPH (blood loss >500 mL) were randomly assigned active management of the third stage (prophylactic oxytocic within 2 min of baby's birth, immediate cutting and clamping of the cord, delivery of placenta by controlled cord traction or maternal effort) or expectant management (no prophylactic oxytocic, no cord clamping until pulsation ceased, delivery of placenta by maternal effort). Women were also randomly assigned upright or supine posture. Analyses were by intention to treat. FINDINGS: The rate of PPH was significantly lower with active than with expectant management (51 [6.8%] of 748 vs 126 [16.5%] of 764; relative risk 2.42 [95% CI 1.78-3.30], p<0.0001). Posture had no effect on this risk (upright 92 [12%] of 755 vs supine 85 [11%] of 757). Objective measures of blood loss confirmed the results. There was more vomiting in the active group but no other important differences were detected. INTERPRETATION: Active management of the third stage reduces the risk of PPH, whatever the woman's posture, even when midwives are familiar with both approaches. We recommend that clinical guidelines in hospital settings advocate active management (with oxytocin alone). However, decisions about individual care should take into account the weights placed by pregnant women and their caregivers on blood loss compared with an intervention-free third stage.

Constriction↗
PubMed1998

Retinoid X receptor-gamma gene expression is developmentally regulated in the embryonic rodent peripheral nervous system.

The retinoid X receptor-gamma (RXRgamma) is a transcription factor that belongs to the thyroid hormone/retinoid family of nuclear receptors. Previous studies have shown that RXRgamma is expressed in the developing peripheral nervous system (PNS) of chick embryos, but such expression has not been reported previously in rodent embryos. Indeed, the pattern of RXRgamma expression appears to be different between avian and rodent species. Using in situ hybridisation and northern blot experiments we show that RXRgamma is expressed in elements of the PNS in rat and mouse embryos and in postnatal rats. However, unlike the chick, where RXRgamma is expressed from the onset of neural crest migration, rat RXRgamma expression in the dorsal root ganglia and trigeminal ganglia was detectable at 14.5 days post coitum (dpc), but not at 13, 12, or 11 dpc. These data suggest that RXRgamma may have a role in the dorsal root ganglia and trigeminal ganglia of late embryos, and that this could be evolutionarily conserved between chick and rodent. On the other hand, rat RXRgamma transcripts in the facio-acoustic (VII-VIII) ganglion were detectable at 11 dpc in neural crest cells condensing to form this ganglion. We discuss the possible significance of the timing of RXRgamma expression in the developing PNS and suggest that closer examination of the structure and function of the PNS of RXRgamma null mutant mice would be of interest.

Animals↗
PubMed1998

Can some in-hospital cardio-respiratory arrests be prevented? A prospective survey.

The hospital cardiac arrest team is summoned in response to a sudden severe deterioration in a patient's condition. However, clinical experience suggests that some calls to general wards are preceded by a more gradual, possibly treatable decline. We undertook this study to define the extent of the problem and look for features that might enable prediction and prevention of cardiorespiratory arrest. We identified patients on general medical and surgical wards for whom cardiac arrest calls had been made. Their casenotes were examined for documentation of abnormal physical signs and laboratory test results in the 24 h before the call. We noted what doctors and nurses had done after abnormalities had been found. Over a 28-week period, calls were made for 47 patients on these wards. Twenty-four (51%) had premonitory signs. These patients were also less likely to survive to hospital discharge (P = 0.02). We conclude that some cardiorespiratory arrests are predictable. Wider appreciation of the significance of abnormal signs and laboratory test results could lead to prompter involvement of experienced clinicians and more aggressive therapy. Alternatively, as mortality is so high in this group of patients, more patients could be appropriately designated 'not for resuscitation'.

Aged↗
PubMed1998

Pharmacological classification of adenosine receptors in the sinoatrial and atrioventricular nodes of the guinea-pig.

1. The effects of seven agonist and three antagonist adenosine receptor ligands were compared on the guinea-pig sinoatrial (SA) node (isolated right atrium) and atrioventricular (AV) node (perfused whole heart). Single agonist concentration-effect curves were obtained to 5'-N-ethylcarboxamidoadenosine (NECA), R(-)-N6-(2-phenylisopropyl)adenosine (R-PIA), N6-cyclohexyladenosine (CHA), 2-chloroadenosine (CADO),),S(+)-N6-(2-phenylisopropyl)adenosine (L-PIA), 2-phenylaminoadenosine (CV 1808) and N6-aminoadenosine (MeAdo). Adenosine and/or NECA curves were obtained in the absence and presence of the antagonists 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), 9-chloro-2 (2-furanyl)-5,6-dihydro-1,2,4-triazolo[1,5-c]quinazolin-5-imine (CGS15943) and N6-(endonorbornan-2-yl)-9-methyladenine (N-0861). 2. A formal comparison of the agonist and antagonist potency data was made by fitting the data to a straight line using a least squares procedure based on principal components analysis to account for the variance on both axes. The antagonist affinity estimates made on the two assays did not deviate significantly from the line of identity. 3. The agonist p[A]50 data obtained on the two assays did not deviate from the line of identity, indicating that there were no significant differences in potencies between the two assays. The p[A]50 ratio of R-PIA and S-PIA was 1.24+/-0.09 in the SA node and 1.36+/-0.11 in the AV node, indicating no difference in the stereoselectivity of the PIA isomers between the two tissues. 4. The agonist potency and antagonist affinity data obtained are consistent with previous findings showing that the AV and SA node data are pharmacologically indistinguishable and belong to the adenosine A1-receptor class. No evidence for the reported A3-receptor was found.

Adenosine↗
PubMed1998

Third degree anal sphincter tears: risk factors and outcome.

The aim of this retrospective study was to determine the incidence, risk factors and anal symptoms related to third degree tears after vaginal delivery. There were 9,631 vaginal deliveries during the 5-year period studied, with 116 (1.2%) having a third degree tear. Statistically significant risk factors for a third degree tear were primiparity, forceps delivery, episiotomy, fetal birth-weight greater than 4,000 g and increased duration of the second stage of labour. Eighty four of the 116 women were able to be interviewed, and 21 (25%) had anal symptoms related to the tear. Only 3 women had sought help for their symptoms. Twelve women experienced anal incontinence and 2 more required delayed repair of the anal sphincter for incontinence. Third degree tears are a major cause of perinatal and postnatal morbidity. Attention needs to be directed to the prevention of such tears by awareness of the women at risk and to better follow-up and counselling of the women sustaining a tear.

Anal Canal↗
PubMed1998

Oral antimicrobial prophylaxis in bone marrow transplant recipients: randomized trial of ciprofloxacin versus ciprofloxacin-vancomycin.

The optimal oral antimicrobial prophylactic regimen for bone marrow transplant recipients remains to be elucidated. We randomized 84 patients to receive either oral ciprofloxacin or ciprofloxacin plus vancomycin at hospital admission. Patients were monitored for bacteremias and clinical parameters, and stool and throat swab surveillance cultures were performed. The addition of vancomycin resulted in a significant decrease in the frequency of patients with surveillance cultures positive for coagulase-negative staphylococci (stool cultures, 44 versus 23%; throat swab cultures, 37 versus 19%) and alpha-hemolytic streptococci (throat swab cultures, 90 versus 60%). The frequencies of positivity for Candida spp. and gram-negative organisms on surveillance cultures were comparable. Despite these results, no differences in the incidences of bacteremias (12 of 41 versus 12 of 43 patients) or clinical parameters such as number of days to first fever, total number of febrile days, length of stay, and number of transfusions could be demonstrated. Because of a lack of efficacy of vancomycin and emerging problems with vancomycin-resistant isolates, vancomycin should not be used in oral antimicrobial prophylaxis regimens.

Antibiotic Prophylaxis↗
PubMed1998

Estimation of the relative abundance of different Bacteroides and Prevotella ribotypes in gut samples by restriction enzyme profiling of PCR-amplified 16S rRNA gene sequences.

We describe an approach for determining the genetic composition of Bacteroides and Prevotella populations in gut contents based on selective amplification of 16S rRNA gene sequences (rDNA) followed by cleavage of the amplified material with restriction enzymes. The relative contributions of different ribotypes to total Bacteroides and Prevotella 16S rDNA are estimated after end labelling of one of the PCR primers, and the contribution of Bacteroides and Prevotella sequences to total eubacterial 16S rDNA is estimated by measuring the binding of oligonucleotide probes to amplified DNA. Bacteroides and Prevotella 16S rDNA accounted for between 12 and 62% of total eubacterial 16S rDNA in samples of ruminal contents from six sheep and a cow. Ribotypes 4, 5, 6, and 7, which include most cultivated rumen Prevotella strains, together accounted for between 20 and 86% of the total amplified Bacteroides and Prevotella rDNA in these samples. The most abundant Bacteroides or Prevotella ribotype in four animals, however, was ribotype 8, for which there is only one known cultured isolate, while ribotypes 1 and 2, which include many colonic Bacteroides spp., were the most abundant in two animals. This indicates that some abundant Bacteroides and Prevotella groups in the rumen are underrepresented among cultured rumen Prevotella isolates. The approach described here provides a rapid, convenient, and widely applicable method for comparing the genotypic composition of bacterial populations in gut samples.

Animals↗
PubMed1998

Evidence into practice, experimentation and quasi experimentation: are the methods up to the task?

OBJECTIVE: Methodological review of evaluations of interventions intended to help health professionals provide more effective and efficient health care, motivated by the current experience of NHS Research and Development in England. Emphasis upon the forms of research appropriate to different stages in the development and evaluation of interventions, the use of experimental and quasi experimental designs, the methods used in systematic reviews and meta analyses. METHOD: A proposed development process is derived from that used in the development of drugs. The strengths and weaknesses of different experimental and quasi experimental designs are derived from published methodological literature and first principles. Examples are drawn from the literature. RESULTS: Like pharmaceuticals, implementation interventions need to go through several stages of development before they are evaluated in designed experiments. Where there are practical reasons that make random allocation impossible in quantitative evaluations, quasi experimental methods may provide useful information, although these studies are open to bias. It is rare for a single study to provide a complete answer to important questions, and systematic reviews of all available studies should be undertaken. Meta analytic techniques go some way towards countering the low power of many existing studies, reduce the risk of bias, and avoid the subjective approaches that may be found in narrative reviews. CONCLUSIONS: The initiative taken by NHS Research and Development in examining methods to promote the uptake of research findings is welcome, but will only prove helpful if careful attention is paid to the different stages of the development process, and different research approaches are used appropriately at different stages.

Humans↗
PubMed1998

Development of an aromatherapy service at a Cancer Centre.

The aromatherapy service at the Cancer Support and Information Centre (CSIC) of this regional Cancer Centre has been continually assessed since its inception in 1993. New methods of assessing complementary therapies, based on the 'therapy-as-practised', have been explored. The present study evaluates the service following changes made after an initial pilot. The professional aromatherapist developed an evaluation tool, and formal questionnaires were limited to the Hospital Anxiety and Depression Scale (HADS). HADS was completed before and after a course of six aromatherapy sessions. Of 89 patients referred, 58 patients completed the six sessions. Referrals were made by health professionals working in the Cancer Centre and in the CSIC. The majority of patients were female with breast cancer and were receiving radical oncological treatment. Tension, stress and anxiety/fear were the most common reasons for referral, and this was reflected in high initial HADS scores. There were significant improvements in HADS scores in the 58 patients completing the course (mean anxiety, depression, and combined scores dropped from 8.9 to 6.2 6.1 to 4.0 and 15.0 to 10.2, respectively, P < 0.001). Fifty per cent or more of the sample reported a significant improvement in the eight most commonly assessed symptoms. The therapist was initially cautious about using questionnaires, but she gained confidence in using HADS as an assessment tool. The areas covered by her own evaluation tools were broadly comparable to established instruments such as the EORTC QLQ-C30. We conclude that aromatherapy massage has a role in reducing psychological distress, and improving symptom control in cancer patients. Further service evaluation is needed to promote appropriate referral and effective planning of treatment, and to justify cost. Given the multifaceted nature of complementary therapies, the need to develop new research methodologies is acknowledged.

Adult↗
PubMed1998

Focus groups, program evaluation and the mentally ill: a case study.

This article uses a case example to describe how focus group interviews were utilized in evaluating mental health services for individuals with a serious and persistent mental illness. The method, questions, and recruitment process are summarized along with a description of the focus group interaction. Modifications of logistic procedures and moderator skills are also presented along with the limitations and benefits of using this method for the purpose of evaluation.

Focus Groups↗
PubMed1998

Vision and driving: selective effect of optical blur on different driving tasks.

A test of static (high-contrast) visual acuity is the most prevalent vision test used to screen driver license applicants worldwide, even though research has largely failed to provide convincing empirical evidence for its role in traffic accidents. The purpose of this research was to evaluate the effect of visual acuity degradation on different components of the driving task. Participants were 24 young licensed drivers (15 men, 9 women) with normal vision. Driving performance was measured while participants wore modified swimmer's goggles to which blurring lenses were affixed in amounts necessary to produce binocular visual acuity levels of 20/20, 20/40 (the prevalent acuity standard for driving), 20/100, and 20/200. Driving performance was measured using the closed-road method of Wood and Troutbeck (1994). Acuity degradation produced significant decrements in road sign recognition and road hazard avoidance as well as significant increments in total driving time. Participants' abilities to estimate whether clearances between pairs of traffic cones were sufficiently wide to permit safe passage of the vehicle and to slalom through a series of traffic cones were relatively unaffected by acuity degradation. Thus the latter tasks appear to be mediated by aspects of central and peripheral vision that are relatively unaffected by optical blur. Potential applications of this type of research include the development of procedures for defining empirically justifiable vision standards for driver licensure.

Adult↗
PubMed1998

Styles of interaction used by learning assistants: the effectiveness of training.

This study examines the effectiveness of a training day for classroom learning assistants (LAs), which aims to change the way LAs interact with language-impaired children. The subjects were eight LA/language-impaired child dyads (with children aged 4;11 to 9;11 years) attending mainstream schools. The dyads were video recorded interacting at two times (before and after training) and in two contexts each time (sharing a book and in class). The training increased the percentage of facilitating utterances and recasts used by the LAs but did not decrease the percentage of controlling utterances used. Although the trained styles of interaction were used more frequently while sharing a book than in a classroom activity, the amount of change following training was not significantly different for these two settings.

Child↗