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Biomedical subjects

C E Duncan

Publications and source records attributed to C E Duncan.

10 recordsLinked to original sources
PubMed1988

Blood lead and associated risk factors in Ontario children.

The purpose of this study was to determine blood levels in Ontario children and to identify those risk factors associated with higher blood lead levels. A random sample of 1315 children aged 7 and younger from urban, suburban and rural Ontario was selected. Blood lead concentration was determined in finger prick blood samples by graphite furnace atomic absorption spectrophotometry. Measurements of lead in air, tap water, soil, and gasoline were also established. Traffic pattern were determined in each area. A questionnaire was administered to a random sample of 800 families of the children tested to assess the presence of other risk factors. Urban children had higher geometric mean blood lead levels (12.02, S.D. = 4.4 micrograms/dl) than suburban children (9.95, S.D. = 3.5 micrograms/dl), and they, in turn, had higher blood lead levels than rural children (8.91, S.D. = 3.9 micrograms/dl). Each of these differences is statistically significant (p less than 0.001). Fifty four (4.3%) of all children were at or above the alert level of 20 micrograms/dl. The proportion above the alert level did not differ significantly between urban, suburban and rural children. Blood lead levels were slightly higher for males than females and for pre-schoolers aged 3 and 4, compared to school age children aged 5 and 6. The blood lead levels of these children were significantly lower than that of children surveyed near a point source of industrial emissions. Multivariate statistical modelling resulted in a set of characteristics which best explained the differences in children's blood lead levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1986

The pathogenesis of stereocilia abnormalities in acoustic trauma.

Stereocilia abnormalities develop in anesthetized guinea pigs within two minutes of exposure to loud sound (3 kHz, 125 dB SPL). Displacement, fracture, fusion and membrane rupture were observed well before the development (after 10 or more minutes) of fine structural changes to other cytoplasmic organelles within the hair cells. Thus stereocilia abnormalities can arise very rapidly due to the direct effects of noise on their microfilaments, cross linkages and limiting membranes. Such abnormalities are thus not necessarily secondary to changes in the body of the affected hair cells.

Actin Cytoskeleton↗
PubMed1974

Suicide notes.

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Authorship↗
PubMedDate not supplied

Bovine blood lead reference material.

A protocol is described for the preparation and characterization of bovine blood lead (Pb) reference material (RM). Adult bovine animals are orally dosed with Pb as Pb(NO3)2, and blood is collected directly from the jugular vein into 5-mL evacuated, low-Pb glass tubes containing EDTA as anticoagulant. The blood is cooled to 4 degrees C for 24 h and frozen and stored at -20 degrees C. Over 400 RMs were prepared and certified for reference values (RV) since the inception in 1974 of the Childhood Blood Lead Proficiency Testing Program. Five reference laboratories employing blood Pb methods of various principles were used to certify the RV, representing the true value, of 5 representative RMs containing 6.4-54.0 micrograms Pb/mL. Intertube homogeneity was verified by reference laboratories determining blood Pb in 20 tubes of 150 tubes collected from each of the 5 representative RMs. Intratube homogeneity was verified by an internal laboratory determining Pb in 12 consecutive 10-microL samples from 5 mL of blood in each of 3 representative RMs. Pb was unchanged in 37 bovine blood Pb RMs containing EDTA as anticoagulant after storage at -20 degrees C for 32-48 months.

Animals↗
PubMedDate not supplied

Use of a ramp surface for lower extremity exercise with burn-injured patients.

The use of a ramp surface in our Burn Center has demonstrated benefits in improving gait, standing postures, and lower extremity muscle length. This technique has been effective with a wide age range of patients and is most useful as part of an overall treatment program including prestretching of lower extremities.

Burns↗
PubMedDate not supplied

The ion exchange properties of human post-mortem caecal and colonic mucus: the effect of sodium butyrate.

This study examined Na+/H+ ion exchange of caecal and colonic mucus. Two distinct Na+/H+ ion exchange populations of caecal mucus were identified, one group being a cation exchanger and the other an anion exchanger, suggesting that caecal mucus has ampholyte properties responsive to changing physical and chemical properties of luminal contents. Mucus from the colon was consistently an anionic exchanger--this may aid water and electrolyte absorption in the colon. When mucus was incubated with sodium butyrate, the Na+/H+ ion exchange properties of the mucus were decreased.

Adolescent↗