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Biomedical subjects

I Turner

Publications and source records attributed to I Turner.

At least 19 recordsLinked to original sources
PubMed2005

Measuring the fate of plant diversity: towards a foundation for future monitoring and opportunities for urgent action.

Vascular plants are often considered to be among the better known large groups of organisms, but gaps in the available baseline data are extensive, and recent estimates of total known (described) seed plant species range from 200000 to 422000. Of these, global assessments of conservation status using International Union for the Conservation of Nature (IUCN) categories and criteria are available for only approximately 10000 species. In response to recommendations from the Conference of the Parties to the Convention on Biological Diversity to develop biodiversity indicators based on changes in the status of threatened species, and trends in the abundance and distribution of selected species, we examine how existing data, in combination with limited new data collection, can be used to maximum effect. We argue that future work should produce Red List Indices based on a representative subset of plant species so that the limited resources currently available are directed towards redressing taxonomic and geographical biases apparent in existing datasets. Sampling the data held in the world's major herbaria, in combination with Geographical Information Systems techniques, can produce preliminary conservation assessments and help to direct selective survey work using existing field networks to verify distributions and gather population data. Such data can also be used to backcast threats and potential distributions through time. We outline an approach that could result in: (i) preliminary assessments of the conservation status of tens of thousands of species not previously assessed, (ii) significant enhancements in the coverage and representation of plant species on the IUCN Red List, and (iii) repeat and/or retrospective assessments for a significant proportion of these. This would result in more robust Sampled Red List Indices that can be defended as more representative of plant diversity as a whole; and eventually, comprehensive assessments at species level for one or more major families of angiosperms. The combined results would allow scientifically defensible generalizations about the current status of plant diversity by 2010 as well as tentative comments on trends. Together with other efforts already underway, this approach would establish a firmer basis for ongoing monitoring of the status of plant diversity beyond 2010 and a basis for comparison with the trend data available for vertebrates.

Biodiversity↗
PubMed2004

Optimum cardiopulmonary resuscitation for basic and advanced life support: a simulation study.

Optimum cardiopulmonary resuscitation (CPR) for both basic and advanced cardiac life support depends on a compromise between the number of chest compressions delivered and the amount of ventilation provided. This study used theoretical models of blood flow and both arterial and venous blood gas values to investigate the influence of different compression to ventilation ratios on CPR efficiency, as well as the effects of different inspired oxygen concentrations. With mouth-to-mouth ventilation, greater numbers of compressions between each ventilation provided progressively greater blood flow. However, a greater the number of compressions, reduced the arterial oxygen levels and carbon dioxide clearance. There was an optimum ratio, in terms of both oxygen delivery and carbon dioxide clearance, of around 20:1 compressions to ventilation. Optimum oxygen delivery was 0.19 L/min at 20:1, which was better than the oxygen delivery for standard CPR based on a ratio of 15:2 (0.13 L/min). When patients were ventilated with supplemental oxygen (either 50 or 85%) the lungs rapidly became saturated with oxygen, and oxygen delivery depended more on blood flow. Higher numbers of compressions provided greater oxygen delivery, but at the cost of increasing hypercarbia, which is thought to affect resuscitation success rates adversely. The simulation results suggested ratios around 20:1 would be the best compromise between blood flow, oxygen delivery (0.25 L/min) and avoidance of hypercarbia. The best results were provided by continuous chest compressions and simultaneous, asynchronous ventilation in an intubated patient. Arterial and venous oxygen and carbon dioxide levels were well maintained, with very good oxygen delivery (0.32 L/min). Intubation with continuous chest compressions and asynchronous ventilation can therefore significantly improve the quality of CPR as a whole, and not just ventilation.

Carbon Dioxide↗
PubMed2002

Does the compression to ventilation ratio affect the quality of CPR: a simulation study.

Experience has shown that better quality CPR leads to a greater chance of a patient surviving a cardiac arrest. Simple CPR techniques, such as using only chest compressions, lead to better skill retention and greater willingness to attempt resuscitation on strangers. However, it is not clear from clinical or experimental studies whether such techniques offer any physiological benefit over more usual 5:1 or 15:2 compression:ventilation ratios. Computer simulations of blood flow and gas exchange during CPR showed that continuous chest compressions produced much greater blood flow (1.39 l/min) than 5:1 (0.73 l/min), 15:2 (0.86 l/min) or 50:5 (0.94 l/min) ratios. However, the ratio of 5:1 produced the highest arterial oxygen levels, with continuous chest compressions the lowest. The most appropriate measure of CPR efficiency appears to be the amount of oxygen delivered to the body during CPR. The ratios of 15:2 and 50:5 produced significantly greater oxygen delivery to the body than 5:1, the greater blood flow with these techniques offsetting the slightly lower arterial oxygen levels. The best oxygen delivery was provided by continuous chest compression in the early stages of CPR. After 3-4 min however, hypoxia meant that continuous compressions became worse than the other techniques. Spontaneous gasping by the patient during CPR was able to extend the effectiveness of chest compression only CPR for much longer.

Blood Gas Analysis↗
PubMed2001

Troponin I chimera analysis of the cardiac myofilament tension response to protein kinase A.

Viral-mediated gene transfer of troponin I (TnI) isoforms and chimeras into adult rat cardiac myocytes was used to investigate the role TnI domains play in the myofilament tension response to protein kinase A (PKA). In myocytes expressing endogenous cardiac TnI (cTnI), PKA phosphorylated TnI and myosin-binding protein C and decreased the Ca2+ sensitivity of myofilament tension. In marked contrast, PKA did not influence Ca2+-activated tension in myocytes expressing the slow skeletal isoform of TnI or a chimera (N-slow/card-C TnI), which lack the unique phosphorylatable amino terminal extension found in cTnI. PKA-mediated phosphorylation of a second TnI chimera, N-card/slow-C TnI, which has the amino terminal region of cTnI, caused a decrease in the Ca2+ sensitivity of tension comparable in magnitude to control myocytes. Based on these results, we propose the amino terminal region shared by cTnI and N-card/slow-C TnI plays a central role in determining the magnitude of the PKA-mediated shift in myofilament Ca2+ sensitivity, independent of the isoform-specific functional domains previously defined within the carboxyl terminal backbone of TnI. Interestingly, exposure of permeabilized myocytes to acidic pH after PKA-mediated phosphorylation of cTnI resulted in an additive decrease in myofilament Ca2+ sensitivity. The isoform-specific, pH-sensitive region within TnI lies in the carboxyl terminus of TnI, and the additive response provides further evidence for the presence of a separate domain that directly transduces the PKA phosphorylation signal.

Actin Cytoskeleton↗
PubMed2000

Overexpression of cyclin D1 mRNA in colorectal carcinomas and relationship to clinicopathological features: an in situ hybridization analysis.

Increased expression of a key cell cycle regulator, cyclin D1, may have relevance to carcinogenesis and clinicopathological characteristics of some cancers. This study represents the first application of in situ hybridization, ISH, to detect cyclin D1 mRNA in tissue sections from colorectal carcinomas. This approach was selected because of its unique potential to clarify whether increased expression of cyclin D1 mRNA correlates with clinical and pathological parameters. The ISH ofa non-radioactive oligonucleotide probe (Biogenex) was immunocytochemically detected in paraffin embedded sections from biopsy or resection specimens. Tumors ranged from well to poorly differentiated, and from stages A, B, C, and D. Ten year survival data were available on the majority of patients. Intensity of tumor and background (smooth muscle) signals were independently scored from 0 to 3. Overexpressed cyclin D1 mRNA was seen in 86% of cases compared to background. This frequency is similar to that reported for pancreatic carcinoma. The average signal intensity score in tumor foci was 1.9 with a background score of 0.05 (p<001). All cases showed specific staining judged by the cytoplasmic localization and a tumor signal:background ratio >1. Expression did not differentiate cancers based on grade, stage or survival (p>1), but did differentiate carcinoma and severe dysplasia from mild dysplasia. We conclude that ISH of cyclin D1 mRNA is an effective and relatively specific means of detecting activity of this gene in colonic neoplasms. The high frequency of overexpression implies that gene activity by itself is not likely to predict a tumor s biological or clinical behavior. On the other hand, these data suggest that increased cyclin D1 gene activity may be an early event in colorectal carcinogenesis. They also are consistent with findings showing cyclin D1 is inducible by a variety of oncogene products.

Adenocarcinoma↗
PubMed1998

A comparative study of the 1992 and 1997 recovery positions for use in the UK.

In April 1997 the ILCOR Basic Life Support advisory statements were announced in conjunction with changes to the recovery position for use in the UK. This study compared the new and old positions by using a questionnaire to assess how well each position satisfied the ILCOR statements. The study was carried out over six different hospital trusts by eight resuscitation training officers. Each tutor alternately taught the 1992 or 1997 recommended positions. After the practical session each student completed a questionnaire on ease of learning and use of the position, as well as other factors such as spinal stability. They were also asked to score the position when they were placed in recovery by other students. Their competency was assessed using the ALS criteria. Over the duration of the study 687 forms were suitable for analysis. For every question there was a significant trend in favour of the 92 position, with students finding the technique easier to learn and use, simpler for positioning for CPR and with less spinal movement during rolling. Possible sources of bias such as previous training, tutor or staff grade made no statistical difference to the results. When performed competently the 1997 position appears to cause less brachial compression, but other problems with learning or use of the 97 position outweigh this advantage. The 1992 position currently provides the best compromise between ease of use, spinal stability and other factors, and better satisfies the ILCOR advisory statements.

Attitude of Health Personnel↗
PubMed1995

Hybrid time-frequency adaptive filtering for the recovery of ventricular late potentials.

Ventricular late potentials are small ECG components that have significant diagnostic importance. Temporal averaging is used to recover these signals from high levels of background noise, but is not the optimum approach. A new form of hybrid time-frequency adaptive filtering is introduced that is based on signal division into a series of frequency bands. This technique is able to process the averaged data further and to reduce significantly the noise levels beyond that achieved by simple averaging. Examples of the processing are shown and its applicability is discussed.

Algorithms↗
PubMed1994

Measurement of the forces and movements involved in neonatal hip testing.

The screening for Developmental Dysplasia of the Hip in infants relies on the two manipulative tests developed by Ortolani and Barlow which are often poorly performed. This study investigated the forces applied and the sequences of physical manoeuvres underlying the tests in order to define a standard of safe practice. Eight subjects examined the hips of two training models that closely simulated the behaviour of a range of infant hip pathologies. The forces applied and the manoeuvres employed during each examination were recorded using a purpose-built force and displacement transducer system. The analysis concentrated on the peak forces and the biomechanical conditions necessary to detect an abnormality. The models' legs had to be abducted beyond certain critical angles in order to dislocate and relocate an unstable femoral head and the magnitude of the force required to dislocate the femoral head was significantly less than the peak force applied (12 N vs 33 N, p < 0.001). Also, the Palmen test, a less well known technique, provided the same level of diagnostic performance as the Barlow test but with a lower peak applied force (28 N vs 47 N, p < 0.001). Changes are therefore necessary to the training programmes for medical staff to ensure that the range of abduction during the manoeuvres is large enough to encompass the likely range of critical angles and that the forces applied are just sufficient so as not to overstress the joints.

Biomechanical Phenomena↗
PubMed1994

Reliability of the Barlow and Ortolani tests for neonatal hip instability.

OBJECTIVE: To investigate if those responsible for screening for neonatal hip instability are using acceptable manual hip stress tests as described by Ortolani and Barlow. METHOD: A video camera was used to record the technique of 35 personnel who were responsible for screening. They examined both a baby and a simulator. The study comprised five groups, classified by experience and practice: senior orthopaedic surgeons, senior paediatric staff, junior paediatric staff, nurses, community staff. RESULTS: The seven authors together with six independent expert observers viewed the video and marked the performance with the aid of a specially designed proforma. Although there was some variation between these expert observers, the results showed differences in the scores obtained by the different groups of examiners over all aspects of the test procedure. CONCLUSION: Video recording for critical analysis and feedback is a useful technique in this situation. Overall, the results suggest that testing for neonatal hip instability was inadequate. A variety of hip stress manoeuvres were being performed. The ability of each subject to perform satisfactory tests seemed to depend on their experience and education. More "hands on" training and experience of testing might provide the necessary competency for screening.

Community Health Nursing↗
PubMed1994

The effect of life domains on girls' possible selves.

Adopting a framework of "possible selves," this paper examines the relative importance of life domains by exploring the suggestion that women's work orientation can be identified as careerist, adaptive or home-centered, and that the choices women make about employment are made relatively early (Hakim, 1991). Sixth-form grammar school girls (N = 240) taking advanced level subjects were categorized as careerist or noncareerist, and differences between the two groups in terms of attainment, subject choice, attitudes toward career and family, interests and confidence in traditional and nontraditional occupations, and psychological variables such as general self-efficacy, sex-role orientation, person/object orientation, scholastic competence, autonomy, and self-worth were examined. It is suggested that work orientation and the importance of life domains may be useful factors to consider in girls' possible selves and may add to the wide-ranging debate as to why girls are underrepresented in the higher status, higher earning occupations.

Adolescent↗
PubMed1993

Re-evaluation of the metabolism of carbocisteine in a British white population.

It has been claimed that the amino acid derivative carbocisteine is predominantly metabolized by sulfoxidation and that this pathway exhibits a genetic polymorphism. Moreover, those subjects with a 'poor metabolizer' phenotype have been thought to have a genetic predisposition to developing certain diseases. We have confirmed the observations of others that this marker drug does not undergo significant S-oxidation. Furthermore, a novel urinary metabolite, S-(carboxymethylthio)-L-cysteine (CMTC) has recently been identified. To determine if a genetic polymorphism for this biotransformation pathway exists, metabolic ratios (% urinary excretion carbocisteine/% urinary excretion CMTC) for 120 healthy volunteers were assessed using high-performance thin-layer chromatography. Urinary excretion of the parent drug ranged from 6% of the dose administered to 56% (mean +/- SD, 23.4 +/- 0.8%). No cysteinyl sulfoxide metabolites were identified in the urine samples. The amount excreted as CMTC exhibited a 12-fold variation but only accounted for mean of 4.4% (1-12%) of the dose given. Two individuals initially had high metabolic ratios (> 30), however, on rechallenge both their MRs were less than 5. Therefore, carbocisteine is not an appropriate probe drug for sulfoxidation. The formation of the novel metabolite CMTC appears to exhibit polymorphism, although the considerable intra-subject variation for its formation does not allow assignment of a phenotype.

Adult↗
PubMed1992

Anti-mitochondrial antibody IgG subclass distribution and affinity in primary biliary cirrhosis.

We have studied the total IgG subclass and anti-mitochondrial antibody (AMA) specific IgG subclass distribution in primary biliary cirrhosis (PBC) sera. In order to solve the problems caused by the differing affinities of subclass specific monoclonals and the competitive inhibition of antibodies in a whole serum assay, six sera were separated into subclass-specific fractions by affinity-depletion chromatography. AMA subclass distribution of 20 further sera from patients with PBC was assessed using conventional methods and the results were calibrated against one of the fractionated sera. Light chain distribution and AMA functional affinity were also assessed for the fractionated subclasses. Total amounts of IgG3 were significantly increased compared with normal controls. AMA were found in all IgG subclasses and not restricted predominantly to IgG3 as previously described. The functional affinity of IgG3 AMA is generally lower as compared with that of other subclasses. No light chain restriction was found.

Animals↗
PubMed1992

Post-primary school pupil's interest in physical education: age and gender differences.

Interest in Physical Education (PE) was studied in 3,344 11 to 18 year-old school children. Five aspects of educational importance (PE connotation, PE status, PE teacher, PE curriculum, and adolescent disturbances in relation to the PE lesson) were identified, and examined in relation to pupils' interest. For the younger age groups girls' interest in PE was significantly higher than that of the boys, while after the age of 14 the reverse was the case. The status of PE as a school subject was found to be the most important variable for interest in PE. The contribution of the PE teacher to pupils' level of interest was the least important of the factors examined. The results are discussed in terms of the differing importance for boys and girls of sport in social status systems for peer popularity. Suggestions for changes to PE lessons are offered.

Adolescent↗
PubMed1991

Quantitative analysis of signal-averaged P waves in idiopathic paroxysmal atrial fibrillation.

Detailed analysis of the QRS complex can identify patients at risk from ventricular arrhythmias, but similar techniques applied to the atria have been disappointing. This study attempts to quantitate differences in the fine morphology of P waves in a group of 9 patients with paroxysmal atrial fibrillation (AF) versus 15 control subjects. Atrial triggered signal-averaging was combined with a detailed investigation of P-wave duration, high-frequency spatial voltage and spatial velocity. Signal-averaged P-wave duration was significantly increased in patients with paroxysmal AF (135 +/- 8 vs 126 +/- 4 ms, p less than 0.05). The root-mean-square voltage at frequencies greater than 35 Hz in these patients was also significantly greater (16 +/- 3 vs 12 +/- 1 microV, p less than 0.05). Similar observations were made at frequencies greater than 40 Hz (10 +/- 3 vs 7 +/- 1 microV, p less than 0.05). These differences appeared to be confined to the third quarter of the P wave (third quarter root-mean-square voltage at greater than 40 Hz expressed as a ratio of total P-wave root-mean-square voltage, 1.4 +/- 0.1 vs 1.2 +/- 0.1, p = 0.005). Spatial velocity was also increased in the paroxysmal AF group (peak spatial velocity 6.4 +/- 1.8 vs 4.6 +/- 0.5 mV/s, p less than 0.05). These observations support previous intracardiac data that implicate delay and fragmentation of intraatrial conduction in the pathogenesis of paroxysmal AF.

Adult↗
PubMed1989

Teachers' and boys' and girls' perceptions of competence in the primary school: the importance of physical competence.

Research into the role of teachers in maintaining self-concepts which reflect gender stereotypes has been hampered by the lack of parallel multidimensional instruments. The development of the Teachers' Rating Scale of the Child's Competence (TRSCC) and the Perceived Competence Scale for Children (PCSC) (Harter, 1982) answers this problem. Thirty-six boys and 38 girls of mean ages 10 years 8 months (SD = 3.6 months) and 10 years 9 months (SD = 3.3 months) respectively completed the PCSC while their teachers (N = 12) completed the TRSCC. It was found that: (1) teachers' mean ratings of boys' competence did not significantly differ from their ratings of girls' competence; (2) teachers' ratings demonstrated significant differences between boys and girls in the pattern of interrelationships of the domains of competence; (3) teachers' perceptions and pupils' self-perceptions in the patterns of interrelationships amongst the domains of competence showed similar patterns for teachers and boys, and almost similar patterns for teachers and girls; (4) teachers were more important for girls' self-perceived competence than for boys' self-perceived competence; (5) both teachers and pupils use perceived physical competence as a construct associated with significantly differentiating between boys and girls in other domains of competence. These findings have pedagogical implications for the treatment of girls.

Achievement↗