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Biomedical subjects

D Evans

Publications and source records attributed to D Evans.

At least 127 records · Page 7Linked to original sources
PubMed1998

Understanding pedestrians' road crossing decisions: an application of the theory of planned behaviour.

This paper reports a study applying the Theory of Planned Behaviour (TPB) to the prediction of pedestrians' road crossing intentions. Respondents (N = 210) completed questionnaires which included scenarios of three potentially dangerous road crossing behaviours, followed by measures of attitude, subjective norm, perceived behavioural control, self-identity and intention. The results indicated that the social psychological variables under consideration were able to explain between 39 and 52% of the variance in intentions to cross the road in the manner depicted in the scenarios. The perceived behavioural control component of the TPB emerged as the strongest predictor of pedestrians' intentions, suggesting that perceptions of control have an important role to play in road safety behaviour. The results are discussed in relation to the predictive utility of the TPB in this area and possible interventions to encourage safe road crossing behaviour.

Accidents, Traffic↗
PubMed1998

Varied redox forms of teleost IgM: an alternative to isotypic diversity?

Teleosts (bony fish) are thought to primarily or exclusively possess a single structural form of immunoglobulin (Ig), a tetrameric IgM. However, in species wherein intact Ig has been electrophoretically analyzed under denaturing, non-reducing conditions, a significant degree of structural diversity has been revealed. This IgM molecule appears to be assembled with great latitude in the degree of disulfide crosslinking between monomeric or halfmer subunits composing the complete IgM molecule. This heterogeneity in the basic structure (herein referred to as redox forms) is not due to isotypic differences as each B cell produces this heterogeneity within its immunoglobulin product. Additionally, in the case of the catfish, a single fish/mouse chimeric Ig H gene is capable of producing IgM with a comparable amount of structural heterogeneity within the mouse cell. Thus, the piscine B lymphocyte routinely assembles a variety of redox forms from one IgM chain. This has both profound biosynthetic implications for macromolecular assembly processes as well as intriguing possibilities for the generation of teleost Ig functional diversity.

Animals↗
PubMed1998

Heidelberg retinal flowmetry: factors affecting blood flow measurement.

AIMS: To evaluate factors affecting Heidelberg retinal flowmeter (HRF) measurements of retinal and optic nerve head blood flow in human subjects. METHODS: The angle of incidence between laser beam and fundus, and camera distance from the eye, were evaluated for their effect upon measures of blood volume, velocity, and flow in a single 100 x 100 x 400 microns volume of temporal peripapillary retinal tissue in normal volunteers. Both intra and intersession reproducibility of these measures were studied. Intersession data were obtained by taking one image per week for 4 weeks. Finally, the intersession haemodynamic data were examined in the entire image (640 x 2560 x 400 microns), using histograms of pixel by pixel blood flow. RESULTS: Measures of blood volume, velocity, and flow from a single anatomical site were unaffected by laser beam to fundus angle of incidence (n = 12). As camera distance from the eye was increased (from 2 to 5 to 7 cm), flow measurements showed increasing individual changes, despite unaltered measured vessel lengths and constant overall mean flow (n = 14). The coefficient of variation for two intersession images of optic nerve head blood flow averaged 7% (n = 20); in contrast, the 4 week intersession coefficient of variation averaged 30% (n = 15). Intersession reproducibility was increased by using flow histograms from the entire image: the coefficients of variation averaged 16% for total flow and 17% for flow in the pixel of median flow. CONCLUSION: HRF measures of flow are independent of the laser beam to fundus angle of the incidence and dependent upon camera distance from the eye. Intersession reproducibility is best using pixel by pixel analysis of the entire image.

Blood Flow Velocity↗
PubMed1998

Neonatal seizures.

Explore the source record for details and available documents.

Anticonvulsants↗
PubMed1998

Outcome at 5-6 years of prematurely born children who received morphine as neonates.

AIM: To assess outcome at 5-6 years in a cohort of very preterm infants (< 34 weeks of gestation) who had been randomly allocated within a controlled clinical trial to receive morphine or non-morphine treatment in the neonatal period. METHODS: Assessments were made on 87 children at 5-6 years who had been recruited in the neonatal period to two sequential controlled studies (1989-92). Infants requiring mechanical ventilation had been randomly allocated to receive either morphine (n = 62) or other (n = 33) solutions starting on the first day of life. Each child was seen by a single experienced observer and assessed at 5-6 years using the WPPSI-R, Movement ABC, and the Child Behaviour Checklist. The performance of children exposed to morphine was compared with that of those in the non-morphine group. Blood samples for thyroid stimulating hormone (TSH) measurement were obtained from children whose parents gave consent. RESULTS: There was no significant difference in any of the three test scales between infants in the two groups, but there was a trend towards better performance in all three tests in the morphine group. Assessment of TSH values in a subgroup of the survivors showed no difference in thyroid function between the two groups. CONCLUSION: Exposure to morphine in the neonatal period to facilitate mechanical ventilation does not seem to have any adverse effects on intelligence, motor function, or behaviour when these children are assessed at 5-6 years of age.

Anesthesia↗
PubMed1998

Impact of education for physicians on patient outcomes.

OBJECTIVES: This study was conducted to assess the impact of an interactive seminar based on self-regulation theory on 1) the treatment practices and communications and education behavior of physicians, 2) the health status and medical care utilization of their pediatric patients with asthma, and 3) the satisfaction with care of the subjects' parents. METHODS: A total of 74 general practice pediatricians were assigned to either a program or a control group in a randomized controlled study. Data were collected from physicians at baseline, and 69 (93%) provided follow-up data 5 months after the program. Data were also collected from 637 of their patients at baseline, and in a 22-month window after the intervention, 472 (74%) of this number provided follow-up data. RESULTS: After the seminar, physicians in the program group were more likely than were control group physicians to address patients' fears about medicines, review written instructions, provide a sequence of educational messages, write down how to adjust the medicines at home when symptoms change, and report that they spent less time with their patients. Parents of the children treated by program physicians were significantly more likely than were control group parents to report that the physician had been reassuring, described as a goal that the child be fully active, and gave information to relieve specific worries. After a visit with the physician, these parents were also more likely to report that they knew how to make management decisions at home. After the intervention compared to controls, patients of physicians in the program group were more likely to have received a prescription for inhaled antiinflammatory medicine and to have been asked by the physician to demonstrate how to use a metered-dose inhaler. After the intervention, children seen by program physicians made significantly fewer nonemergency office visits and visits for follow-up of an episode of symptoms; however, there were no differences in emergency department visits and hospitalizations. Among children who were placed on inhaled corticosteroids during this study, however, children treated by physicians who had received education had significantly fewer symptoms and fewer follow-up office visits, nonemergency physician office visits, emergency department visits, and hospitalizations. CONCLUSIONS: The interactive seminar based on theories of self-regulation led to patient-physician encounters that were of shorter duration, had significant impact on the prescribing and communications behavior of physicians, led to more favorable patient responses to physicians' actions, and led to reductions in health care utilization.

Asthma↗
PubMed1998

Compound heterozygosity for a new (S259G) and a previously described (G188E) mutation in lipoprotein lipase (LpL) as a cause of chylomicronemia. Mutations in brief no. 183. Online.

Familial chylomicronemia is an autosomal recessive disease characterised by fasting triglyceridemia and an absence of lipoprotein lipase (LpL) activity in post-heparin plasma. The disease is a result of mutation in either the lipoprotein lipase (Lpl) gene or in the apoCII gene which codes for an essential co-factor. To date, over 80 mutations in the LpL gene have been reported. The proband, a 30 month old female, presented with fasting triglycerides of 3192 mg/dl, and no detectable LpL mass or activity in post-heparin plasma. Sequencing of all of the exons and exon/intron boundaries of the LpL gene showed that she was a compound heterozygote with G-A transitions in codon 188 (G188E:GGG to GAG) generating an avall restriction site and in codon 259 (S259G:AGT to GGT) generating a bssKI site. Restriction digests confirmed the mutations and determined the incidence within the family. The father (55%LPL activity), paternal aunt (82%) and paternal grandmother (29%) were all heterozygous for the S259G mutation whilst her sister (55%), mother (73%) and maternal grandfather (45%) were heterozygous for the G188E mutation. The maternal grandmother (114%) was unaffected.

Female↗
PubMed1998

The continuum of care: the process and development of a nursing model for stroke education.

A recent focus in health care is to develop a seamless transition for patients between the variety of health care agencies with whom they interact. The continuum of care for patients with stroke is complex and many levels of care are required, from acute intervention through to rehabilitation and reintegration into the community. A group of nurses from a variety of agencies in Southwestern Ontario received funding from the Ontario province Wide Nursing Project to effect a desirable change in the way nurses care for the stroke patient. This article describes the Ontario Province Wide Nursing project and the process of and challenges in developing a nursing model for stroke. The development of a nursing model for stroke patients and their families involved conducting nursing, and patient and family focus groups to identify key issues. Thirty-eight nurses participated in the nursing focus groups, and 8 patients and 18 family members participated in the patient and family focus groups. The common themes were the need for improved communication and the need to better prepare patients and families for the many transitions they experience during their recovery from stroke. A Stroke Education Record, which identifies a comprehensive list of potential learning needs of stroke patients and their families, and a Stroke Education and Resource Guide, which provides a reference for nurses, were developed and will be implemented in September 1998. Implementation of the model included a workshop, staff inservices, a self-learning package, and unit displays. Evaluation of the model will include nursing and patient and family focus groups, a chart review, written nursing evaluations, and patient and family telephone interviews.

Cerebrovascular Disorders↗
PubMed1997

Operons and SL2 trans-splicing exist in nematodes outside the genus Caenorhabditis.

The genomes of most eukaryotes are composed of genes arranged on the chromosomes without regard to function, with each gene transcribed from a promoter at its 5' end. However, the genome of the free-living nematode Caenorhabditis elegans contains numerous polycistronic clusters similar to bacterial operons in which the genes are transcribed sequentially from a single promoter at the 5' end of the cluster. The resulting polycistronic pre-mRNAs are processed into monocistronic mRNAs by conventional 3' end formation, cleavage, and polyadenylation, accompanied by trans-splicing with a specialized spliced leader (SL), SL2. To determine whether this mode of gene organization and expression, apparently unique among the animals, occurs in other species, we have investigated genes in a distantly related free-living rhabditid nematode in the genus Dolichorhabditis (strain CEW1). We have identified both SL1 and SL2 RNAs in this species. In addition, we have sequenced a Dolichorhabditis genomic region containing a gene cluster with all of the characteristics of the C. elegans operons. We show that the downstream gene is trans-spliced to SL2. We also present evidence that suggests that these two genes are also clustered in the C. elegans and Caenorhabditis briggsae genomes. Thus, it appears that the arrangement of genes in operons pre-dates the divergence of the genus Caenorhabditis from the other genera in the family Rhabditidae, and may be more widespread than is currently appreciated.

Animals↗
PubMed1997

Water fluoridation, tooth decay in 5 year olds, and social deprivation measured by the Jarman score: analysis of data from British dental surveys.

OBJECTIVE: To examine the effect of water fluoridation, both artificial and natural, on dental decay, after socioeconomic deprivation was controlled for. DESIGN: Ecological study based on results from the NHS dental surveys in 5 year olds in 1991-2 and 1993-4 and Jarman underprivileged area scores from the 1991 census. SETTING: Electoral wards in three areas: Hartlepool (naturally fluoridated), Newcastle and North Tyneside (fluoridated), and Salford and Trafford (non-fluoridated). SUBJECTS: 5 year old children (n = 10,004). INTERVENTION: Water fluoridation (artificial and occurring naturally). MAIN OUTCOME MEASURE: Ward tooth decay score (score on the "decayed, missing, and filled tooth index" for each electoral ward). RESULTS: Multiple linear regression showed a significant interaction between Jarman score for ward, mean number of teeth affected by decay, and both types of water fluoridation. This confirms that the more deprived an area, the greater benefit derived from fluoridation, whether natural or artificial (R2 = 0.84, P < 0.001). At a Jarman score of zero (national mean score) there was a predicted 44% reduction in decay in fluoridated areas, increasing to a 54% reduction in wards with a Jarman score of 40 (very deprived). The area with natural fluoridation (at a level of 1.2 parts per million-higher than levels in artificially fluoridated areas) had a 66% reduction in decay, with a 74% reduction in wards with a Jarman score of 40. CONCLUSION: Tooth decay is confirmed as a disease associated with social deprivation, and the more socially deprived areas benefit more from fluoridation. Widespread water fluoridation is urgently needed to reduce the "dental health divide" by improving the dental health of the poorer people in Britain.

Child, Preschool↗
PubMed1997

Dysregulated expression of neutrophil apoptosis in the systemic inflammatory response syndrome.

OBJECTIVE: To study the effect of the systemic inflammatory response syndrome (SIRS) or major elective surgery on the apoptosis of circulating polymorphonuclear neutrophils because an activated inflammatory response is terminated, in part, through the programmed cell death, or apoptosis, of its effector cells. DESIGN: A prospective inception cohort study. SETTING: A mixed surgical and medical intensive care unit of an adult tertiary care hospital. PATIENTS: Sixteen patients with SIRS, 7 uninfected patients who had undergone elective aortic aneurysmectomy, and 8 healthy laboratory control subjects. INTERVENTIONS: Serial blood samples were drawn for evaluation of neutrophil apoptosis, activational state, and surface receptor expression by flow cytometry. MAIN OUTCOME MEASURES: Spontaneous apoptosis was significantly delayed in neutrophils from patients with SIRS (8.6%+/-6.8%) and patients who had undergone elective aortic aneurysmectomy (11.0%+/-5.0%) when compared with controls (34.9%+/-6.8%). These neutrophils were activated as evidenced by enhanced respiratory burst activity and augmented surface expression of CD11b. Apoptosis in response to engagement of cell surface Fas (also known as CD95 or APO-1) with an agonistic antibody was blunted. Plasma from patients with SIRS or patients who had undergone elective aortic aneurysmectomy suppressed the apoptotic responses of control neutrophils (plasma from patients with SIRS, 18.8%+/-10.3%; plasma from patients who had undergone elective aortic aneurysmectomy, 20.0%+/-6.1%; P<.01). Western blot analysis showed normal expression of the key proapoptotic proteases, interleukin 1beta converting enzyme and CPP32 (also known as YAMA, apopain, and caspase 3), indicating that delayed apoptosis was not a consequence of decreased levels of proapoptotic enzymes. CONCLUSIONS: Circulating neutrophils from patients with SIRS or from patients who have undergone major elective surgery show delayed expression of constitutive programmed cell death, and antiapoptotic factors are present in the general circulation. While prolonged neutrophil survival may represent an appropriate adaptive response to injury, the presence of activated and apoptosis-resistant cells in an antiapoptotic environment may contribute to the systemic inflammatory injury characteristic of SIRS and predispose to the development of the multiple organ dysfunction syndrome.

APACHE↗
PubMed1997

Increased living donor volunteer rates with a formal recipient family education program.

We have generally encouraged living donation among our kidney recipients. However, an examination of our clinical practice revealed inconsistencies in the depth and content of information transmitted to kidney recipient families regarding living donation. We therefore initiated a structured education program, including an educational video, to ensure that all recipient families would receive a similar exposure to a standard block of information. After the program had been functioning for over a year, we compared the living donor (LD) volunteer rates between the 3-year period before (BEFORE) and the 18 months after (AFTER) initiation of the formal education program. There were 1,363 patients registered on our kidney transplantation waiting list during the 54-month study period (757 white [56%] and 580 black [43%]). We found that 33.4% of the kidney transplant candidates in the period BEFORE the LD education program had at least one potential LD tissue typed, compared with 39.4% in the period AFTER starting the program (P = 0.03). The increase in the proportion of patients with potential donors was greatest among the black (P < 0.05) and elderly (P < 0.01) registrants, which were the groups with the lowest volunteer rates before the program began. Among the registrants with at least one potential donor, the percentage of registrants who ultimately received an LD transplant was highly correlated with the number of donors (R = 0.98). The rate of LD kidney transplantation was significantly higher (P = 0.02) for the patients referred in the period AFTER initiation of the LD education program compared with the period BEFORE the program. The 1- and 3-year graft survival rates for the 170 LD transplants performed in these patients were 96.9% and 93.2%, respectively. These were significantly better than the corresponding 83.9% and 71.4% rates for the 341 kidney transplants from cadaver donors in these registrants (P < 0.001). Black recipients of LD transplants had graft survival rates comparable to whites; the 3-year graft survival rate for LD transplants was 93.9% in whites and 90.6% in blacks (P = NS). We conclude that living kidney donor volunteer rates can be improved by a formal family education program, especially for subgroups of patients with low volunteer rates. A substantial benefit is derived by black patients, who generally experience low graft survival rates with cadaver-donor kidneys. A local formal LD education program is a useful adjunct to national organ donation campaigns.

Adult↗
PubMed1997

Microembolization during endovascular and conventional aneurysm repair.

PURPOSE: Endovascular aneurysm repair has been advocated as a "minimally invasive" alternative to conventional aneurysm surgery. However, because of manipulation within the aneurysm sac, endovascular techniques may result in massive microembolization. METHODS: In this study lower limb microemboli were quantified in 29 patients undergoing conventional (11 straight and 7 bifurcated grafts) and endovascular aneurysm repair (8 aortoiliac, 1 straight, and 2 bifurcated grafts) by insonation of the superficial femoral artery with a 2 MHz Doppler probe. Emboli were detected as high-intensity, short-duration signals on the background Doppler trace. Differentiation of gaseous emboli from particulate emboli was achieved by calculation of the sample volume length (emboli velocity x duration = sample volume length) for each embolus (N = 4927). Previous experiments had determined that a sample volume length < 1.4 cm represented particulate embolization. RESULTS: The number of gaseous, particulate, and total emboli were significantly greater in the endovascular group compared with the conventional group (p < 0.05). CONCLUSIONS: These data demonstrate that peripheral microembolization is significantly higher during endovascular aneurysm repair than during conventional surgery. Methods to reduce embolization must be developed before endovascular aortic surgery is widely adopted.

Aged↗
PubMed1997

Comparison of open and laparoscopic live donor nephrectomy.

OBJECTIVE: This study compares an initial group of patients undergoing laparoscopic live donor nephrectomy to a group of patients undergoing open donor nephrectomy to assess the efficacy, morbidity, and patient recovery after the laparoscopic technique. SUMMARY BACKGROUND DATA: Recent data have shown the technical feasibility of harvesting live renal allografts using a laparoscopic approach. However, comparison of donor recovery, morbidity, and short-term graft function to open donor nephrectomy has not been performed previously. METHODS: An initial series of patients undergoing laparoscopic live donor nephrectomy were compared to historic control subjects undergoing open donor nephrectomy. The groups were matched for age, gender, race, and comorbidity. Graft function, intraoperative variables, and clinical outcome of the two groups were compared. RESULTS: Laparoscopic donor nephrectomy was attempted in 70 patients and completed successfully in 94% of cases. Graft survival was 97% versus 98% (p = 0.6191), and immediate graft function occurred in 97% versus 100% in the laparoscopic and open groups, respectively (p = 0.4961). Blood loss, length of stay, parenteral narcotic requirements, resumption of diet, and return to normal activity were significantly less in the laparoscopic group. Mean warm ischemia time was 3 minutes after laparoscopic harvest. Morbidity was 14% in the laparoscopic group and 35% in the open group. There was no mortality in either group. CONCLUSIONS: Laparoscopic live donor nephrectomy can be performed with morbidity and mortality comparable to open donor nephrectomy, with substantial improvements in patient recovery after the laparoscopic approach. Initial graft survival and function rates are equal to those of open donor nephrectomy, but longer follow-up is necessary to confirm these observations.

Adult↗