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Biomedical subjects

R E Wright

Publications and source records attributed to R E Wright.

At least 19 recordsLinked to original sources
PubMed2001

Radiation doses to patients during ERCP.

BACKGROUND: There is a scarcity of data regarding the radiation dose and associated risks to patients during ERCP. Dose area product (DAP) measurements can be used to estimate an effective dose (ED) to patients undergoing ERCP. This measure allows radiation risk associated with such procedures to be quantified. The aim of this study was to evaluate the ED to patients undergoing ERCP. METHODS: A DAP meter was fitted to the x-ray tube before each ERCP. DAP reading (Gy-cm(2)), fluoroscopy time, average screening kVp, number of films, and kVp per film were recorded. Mean ED was estimated by using DAP readings and Monte Carlo computer software to model radiation exposure conditions. RESULTS: Data were recorded on 20 subjects. Average DAP was 13.5 Gy-cm(2) (6.8-23.9) for diagnostic and 66.8 Gy-cm(2) (28.7-108.5) for therapeutic ERCP (p < 0.05). Average fluoroscopy time was 2.3 minutes (1.1-5.3) for diagnostic and 10.5 minutes (5.9-16.6) for therapeutic ERCP (p < 0.05). DAP showed a linear relationship with fluoroscopy time (R(2) = 0.928). Mean number of diagnostic and therapeutic films was 2.8 and 3.7, respectively. Fluoroscopic exposure represented 69% of the DAP for diagnostic ERCP and 90% of the DAP for therapeutic ERCP. Average ED was 3.1 mSv for diagnostic and 12.4 mSv for therapeutic ERCP. CONCLUSIONS: Therapeutic ERCP is associated with significantly higher radiation exposure than diagnostic ERCP. ED in therapeutic ERCP is a result largely of fluoroscopy time as opposed to number of films.

Adult↗
PubMed1998

Radiation doses to patients during pharyngeal videofluoroscopy.

Pharyngeal videofluoroscopy (VTF) is a well-recognized technique for investigating and assessing swallowing disorders. There is, however, a paucity of data available regarding the radiation dose to patients during such procedures, but there is general concern that fluorographic imaging modalities are associated with significant radiation exposure. We have recorded the dose received by 23 patients undergoing VTF in our department using a Dose-Area Product (DAP) Meter and have used the data to calculate the effective dose to the patients. The mean effective dose is 0.4 mSv (range 0.027-1.1) which compares favorably with the effective doses associated with other common radiological procedures. We therefore conclude that the radiation detriment associated with pharyngeal VTF is well within acceptable levels.

Adult↗
PubMed1997

Patient perception and localization of dysphagia -- barium study correlation.

We assessed the accuracy of patient localization of the site of dysphagia and its implications for radiological practice during the barium swallow examination. Several current texts dispute the value of such information. Fifty-two consecutive patients with dysphagia were asked to localize the site of discomfort on the skin surface. The ability of each patient to do so precisely or vaguely was noted. A detailed barium examination of the pharynx, esophagus and stomach was performed. Results suggested that patients who had symptoms more cranial than the sternal notch were highly accurate at localizing disease. Localization became less precise as symptoms moved caudally towards the epigastrium. Lateralization of symptoms was highly accurate in determining the site of pathology. In conclusion, we feel that in certain circumstances the barium examination can be usefully tailored to accelerate examination times, thus reducing radiation exposure and cost whilst improving diagnostic accuracy.

Adult↗
PubMed1996

Videofluoroscopic assessment in children with severe cerebral palsy presenting with dysphagia.

In this study 16 patients with severe spastic cerebral palsy with an age range between 6 months and 16 years were examined using videofluoroscopy and a modified barium meal. All patients were slow, inefficient eaters. Silent aspiration was demonstrated in five cases. The latter five patients demonstrated a delayed swallow reflex but there was little correlation between aspiration and the oral phase of deglutition. Our data confirms the impression that early diagnostic workup including videofluoroscopy is helpful in managing the feeding difficulties in these children, and may prevent chronic aspiration and malnutrition.

Adolescent↗
PubMed1996

Risk factors for death and emergency transfer in acute and subacute inpatient rehabilitation.

OBJECTIVES: To compare the risk of death or emergency transfer (ET) to an acute care hospital for acute and subacute rehabilitation inpatients, to identify risk factors, and to determine whether the risk factors vary by level of care. DESIGN: Proportional hazards regression analysis of retrospective cohort data. Explanatory variables included level of care, age, sex, medical stability at admission, and diagnosis. SETTING: An acute inpatient rehabilitation hospital and a skilled nursing facility-based subacute rehabilitation program. PATIENTS: Patients were selected from a database of all acute and subacute inpatients discharged between January 1992 and August 1994 (N = 4,755). Readmissions and pediatric patients were excluded (n = 896). Patients who had complete data (n = 3,185) were included in the survival analysis; a separate univariable analysis was performed for patients who lacked complete data (n = 674). OUTCOME MEASURE: Rate of death or emergency transfer during rehabilitation. RESULTS: The overall risk was greater for subacute patients than for acute inpatients, 20.6% vs 11.6%, odds ratio = 2.0, CI = 1.6 to 2.5. The survival analysis indicated that age, level of care, sex, and stability were associated with the risk of death or emergency transfer (2.1 < or = zeta < or = 4.7; p < .05 for each). However, the difference in risk between subacute and acute care was greatest among younger patients. CONCLUSIONS: Careful consideration of risk factors is critical for proper assignment of patients to rehabilitation levels of care. However, research is needed to test these findings in other settings and to improve identification of high-risk patients.

Aged↗
PubMed1991

Parental education and child mortality in Burundi.

This paper examines the relationship between parental education and child mortality in Burundi using data collected in the 1987 Demographic and Health Survey. Proportional hazards models are estimated to examine this relationship, while holding constant other known child mortality determinants. Parental education proves to be a key factor in explaining differences in child mortality, the effect of maternal education being particularly strong compared to paternal education.

Birth Order↗
PubMed1990

Fecundity of partially engorged female Dermacentor albipictus (Acari: Ixodidae) removed by cattle grooming.

Eight Hereford heifer calves were infested 28 times over a 64-d period with approximately 49,560 Dermacentor albipictus (Packard) larvae per calf. The fecundity of partially engorged and small, fully engorged female ticks, prematurely removed by grooming behavior of the calves, were compared. A total of 3,532 females of various engorged weights was collected from all calves, resulting in a mean female tick yield of 1.78% based on the number of larvae used for all infestations. The ratio of partially to fully engorged females was 1:16. Female oviposition success was 96%. The mean (+/- SE) values for female weight, number of larvae, and percentage larval eclosion of 50 partially engorged females that ranged in weight from 54 to 397 mg was 174 +/- 99, 1,272 +/- 931 and 85 +/- 14, respectively. The correlation between preoviposition weight and number of larvae from partially engorged females was highly significant (r = 0.95, P less than 0.0001). A prediction model (Y = -354.6 + 9.07X) showed that the preoviposition weight of partially engorged females and larval fecundity from a separate study was highly correlated (r = 0.92, P less than 0.0001). There was no significant difference between mean values of larval numbers and percentage eclosion for partially engorged and small, fully engorged females of similar weight.

Animals↗
PubMed1990

Identification of horse flies (Diptera: Tabanidae) by analysis of cuticular hydrocarbons.

Thin-layer chromatography of the cuticular lipids of horse flies from Oklahoma revealed that hydrocarbon was the major lipid class present. The hydrocarbon fraction was composed of n-alkanes and methyl branched alkanes with only a small amount of alkenes present. Gas chromatography of the isolated cuticular hydrocarbons from a single species, Tabanus abactor Philip, showed no major differences in the profiles between individuals or between the sexes. Analysis of extracts of fresh, frozen, and pinned specimens yielded nearly identical hydrocarbon profiles. Profiles of several species were examined and found to be unique for each. Three species with similar morphological characteristics and similar geographical ranges. Tabanus abdominalis F., T. limbatinevris Macquart, and T. sulcifrons Macquart, were differentiated easily by comparison of the hydrocarbon profiles.

Animals↗
PubMed1990

Bovine leukosis virus transmission with mouthparts from Tabanus abactor after interrupted feeding.

A successful attempt was made to mechanically transmit bovine leukosis virus (BLV) from a BLV-infected cow with a normal lymphocyte count to sheep by inoculation with horse fly (Tabanus abactor) mouthparts. After interrupted natural feeding, horse flies were anesthetized with CO2. Mouthparts were severed and pooled into a tissue grinder containing medium. Five inocula containing the mouthparts of 10 flies each, and 5 inocula containing the mouthparts of 20 flies each, were prepared and inoculated SC in the right axilla of 10 BLV antibody-negative sheep. Five additional sheep served as controls. Serum samples were collected at 2-week intervals and tested by agar gel immunodiffusion for BLV antibodies. One sheep injected with 20 mouthparts developed antibodies to BLV at 10 weeks after inoculation. Six months after inoculation with fly mouthparts, 1 BLV antibody-negative sheep was randomly selected from each treatment group and injected, in the left axilla, with 3 ml of blood from the donor cow to confirm susceptibility of the sheep. All 3 sheep developed antibodies to BLV within 4 weeks.

Animals↗
PubMed1989

Population estimation of the horse fly, Tabanus abactor (Diptera: Tabanidae), in northcentral Oklahoma.

A mark-recapture technique was used to estimate daily populations of host-seeking Tabanus abactor Philip. Daily population estimates were calculated for 31 and 37 d for areas of 2.1 km2 and 4.6 km2 for 1982 and 1983, respectively. In 1982, population estimates ranged from 22,767 to 2,125,322 flies/2.1 km2 per d with a mean of 467,277 flies/d. In 1983, population estimates ranged from 48,962 to 2,794,389 flies/4.6 km2 per d with a mean of 759,616 flies/d. The estimated average number of host-seeking females per hectare was 2,225 (0.22 flies/m2) and 1,651 (0.17 flies/m2) for 1982 and 1983, respectively. Although daily population estimates fluctuated greatly, primarily because of fluctuation in recapture rates, seasonal trends during both years were similar. The estimates calculated in this study appear to be representative of the population of T. abactor in northcentral Oklahoma based on previous studies determining seasonal abundance.

Animals↗
PubMed1987

Changes in life expectancy of mentally retarded persons in Canadian institutions: a 12-year comparison.

A 12-year comparison of changes in the distribution of age, sex and level of functioning, as well as in life expectancy for mentally retarded persons in Canadian institutions has been reported. The major findings of the study corroborate, for the most part, studies from other parts of the developed world despite differences in measures of mortality. Several trends have emerged from the data which will have implications for long-term planning.

Actuarial Analysis↗
PubMed1982

Adult age similarities in free recall output order and strategies.

Adult age differences on a variety of free recall measures were examined. Although primary memory capacity was found to be the same in young and old adults, there was a smaller recency effect in the older group. Recall of primacy items was also less for that group. However, the pattern of serial position effects was the same for the two age groups. Similarly, there was no age difference in the development of the strategy of recalling recency items early in the output sequence. Young adults showed the typical negative recency effect in final free recall, and old adults the absence of a positive recency effect. The results indicate that the lower level of recall of old, relative to young, adults cannot be attributed to a qualitative difference in the way the two age groups approach a free recall task.

Adult↗