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Biomedical subjects

B Duncan

Publications and source records attributed to B Duncan.

At least 73 records · Page 4Linked to original sources
PubMed1987

Clinical prediction of cervical spine injuries in children. Radiographic abnormalities.

During the seven-year period from 1976 through 1982, 2133 cervical spine radiographs were obtained for children less than 18 years of age at two hospitals in Tucson. Twenty-five children (1.2%) had x-ray evidence of a cervical spine injury, with a male to female ratio of 4:1. Vehicular accidents accounted for 36% of cervical spine radiographic abnormalities, and sports or playground accidents accounted for an additional 36%. In an attempt to find clinical predictors that might identify x-ray abnormalities, we reviewed the medical records of these 25 children with abnormalities and 713 randomly selected children without x-ray evidence of cervical spine injuries for the following: method of injury, presenting complaints, physical examination findings, therapy, and complications. No single clinical predictor had a sensitivity of 100% when considered in isolation, but clinical assessment consisting of EITHER a complaint of neck pain OR involvement in a vehicular accident with head trauma would have correctly identified all 25 cases of cervical spine injury. If this information had been used prospectively, the number of cervical spine radiographs ordered would have been reduced by 32%. We conclude that the use of this clinical "marker" would have positively identified all children with cervical spine injuries and would have reduced by one third the cost and radiation exposure associated with cervical spine radiographs. Because of the serious consequences of missing a cervical spine injury, we suggest that other studies confirm these results before this information is accepted as a recommendation.

Accidents, Traffic↗
PubMed1987

Anaesthesia for combined heart and lung transplantation.

In December 1983, Harefield Hospital started a programme for combined heart and lung transplantation. Fifty-two transplants have been successfully performed, with 36 survivors (April 1986). Patient selection and anaesthetic management of both donor and recipient are discussed. Two case histories are presented which illustrate the principles of anaesthetic management and postoperative care.

Adolescent↗
PubMed1987

Dipyridamole: pharmacokinetics and effects on aspects of platelet function in man.

1. The effect of dipyridamole on platelet function was measured in twelve normal subjects given 150 or 200 mg tablets as single and multiple doses, and in six subjects given single doses of 25, 50 and 100 mg and multiple doses of 50 mg 8 hourly. 2. Platelet aggregation was measured in response to ADP and collagen. In the subjects given 150/200 mg, the platelets were assayed for content of cyclic AMP and for formation of thromboxane after addition of collagen. The responses to ADP and collagen and the cyclic AMP content were assessed in both the presence and absence of added PGE1. The pharmacokinetics of dipyridamole were studied in all subjects. 3. One hour after 150/200 mg single doses of dipyridamole there was significant inhibition of platelet aggregation in response to both collagen and ADP. There was no detectable effect on aggregation at other time points or with lower doses of dipyridamole. The addition of PGE1 to platelets prior to testing did not enhance the effect of dipyridamole on platelet aggregation. 4. In multiple doses, dipyridamole (150/200 mg twice daily for 11 days) had no detectable effect on platelet aggregation. 5. Dipyridamole did not have any effect on platelet cyclic AMP content, whether or not PGE1 was added prior to assay. 6. Dipyridamole did not affect platelet thromboxane formation. 7. Plasma dipyridamole concentrations were maximal 1-2 h after ingestion, at the same time that inhibition of platelet aggregation was detected. The concentrations declined in a biexponential fashion, with a terminal half life of 24.1 +/- 1.9 h (mean +/- s.e. mean). In six of the 17 subjects, the mean steady state plasma concentration was less than 75% of the value predicted from the single dose data.

Adolescent↗
PubMed1986

Glycine-based oral rehydration solution: reassessment of safety and efficacy.

We evaluated the safety and efficacy of a glycine-based orally administered rehydration solution by comparing it with a standard oral rehydration solution (ORS) without glycine in a randomized double-blind trial in United States infants (age less than 15 months) given treatment for acute gastroenteritis as inpatients or outpatients. The response to therapy (stool volume and duration of illness) was similar in the two groups, except that in four (13%) of 31 hospitalized infants receiving glycine-ORS hypernatremia developed, (one had symptoms) compared with none of 35 receiving ORS (P less than 0.04). Among the 77 outpatients there were no differences between the groups. This study demonstrates that glycine-ORS did not provide any therapeutic advantage over standard ORS, and hypernatremia developed in some patients receiving glycine-ORS. We suggest that caution be used with this type of solution until further safety studies have been done.

Anti-Bacterial Agents↗
PubMed1986

Bicycle helmet use by children: knowledge and behavior of physicians.

A survey of pediatricians and family physicians in Tucson, Arizona revealed that the majority knew that bicycle accidents are an important cause of childhood mortality and were aware that head trauma causes most bicycle-related deaths. Ninety-two per cent knew that children rarely use bicycle helmets and most believed this was due to inadequate parental awareness of the importance of helmets. Despite this, many physicians never include bicycle safety in patient education provided during well-child care.

Adolescent↗
PubMed1986

The association of dyslipoproteinemia with symptoms and signs of peripheral arterial disease. The Lipid Research Clinics Program Prevalence Study.

Intermittent claudication, leg pain during a graded exercise test (GXT), and resting systolic pressures in the upper and lower extremities were recorded as indicators of peripheral arterial disease at visit 2 of the Lipid Research Clinics (LRC) Prevalence Study. Systolic pressures of the upper and lower extremities were measured in a subsample of participants. We compared lipid levels of persons with and without claudication and with or without GXT-induced leg pain. We also compared lipid levels between groups with high and low arm:ankle systolic blood pressure ratios. Twenty-one (1.0%) men, 10 (1.0%) female nonusers and six (1.0%) female users of gonadal hormones had intermittent claudication determined by standardized questionnaire. Men with claudication had lower high-density lipoprotein (HDL)-cholesterol (35.6 vs 46.4 mg/dl), and their mean triglyceride level and cigarette consumption were higher and regular exercise less frequent. Men with type IIb dyslipoproteinemia were more likely to report claudication. One hundred sixty-nine (4.0%) men, 101 (3.8%) female nonusers, and 47 (4.1%) female users of hormones stopped the GXT because of leg pain. Mean HDL-cholesterol levels were lower for those with GXT-induced leg pain in all three sex-hormone usage groups (42.0 vs 46.9, p less than .001; 53.9 vs 59.4, p less than .001; 65.3 vs 67.2, p = NS) and mean low-density lipoprotein cholesterol levels were higher in those with leg pain on GXT in two of three groups (146.4 vs 146.2, p = NS; 155.7 vs 144.6, p less than .01; 144.4 vs 133.5, p less than .05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Iron and the exclusively breast-fed infant from birth to six months.

This study was designed to determine whether normal, full-term, exclusively breast-fed infants develop iron deficiency anemia, as defined by hemoglobin or red blood cell indices more than two standard deviations below the age-specific mean, or depletion of iron stores, as defined by an abnormally low serum ferritin level. Thirty-three breast-fed infants were followed from birth to 6 months. Maternal blood and cord blood at delivery, and venous blood from the infants at 2, 4, and 6 months were analyzed for anemia as defined above. At 6 months of age, the mean hemoglobin concentration of these infants was slightly higher than the normal mean; four of 33 infants (12%) had a mean corpuscular volume greater than 2 SD below the reported normal mean; and two of 33 infants (6%) had a serum ferritin level less than 12 ng protein/ml. These data suggest that the infant who is exclusively breast-fed for the first 6 months of life is not at high risk for the development of iron deficiency anemia or the depletion of iron stores during that time.

Anemia, Hypochromic↗
PubMed1984

Reduced growth velocity in exclusively breast-fed infants.

A number of recent studies have reported reduced growth velocity among breast-fed infants, as compared with standard growth curves. Contradictions between these and previous studies of breast-feeding have been difficult to resolve because of methodological problems, particularly supplementation of breast-feeding with other nutrients. In the present study, 33 term infants, exclusively breast-fed for six months, showed significantly slower rates of growth compared with data from the National Center for Health Statistics (NCHS). Between birth and 6 months of age, these infants lost an average of 20 percentiles in weight for age and 30 percentiles in length in relation to the NCHS population. We discuss these findings in terms of the appropriateness of the NCHS data as standards and the adequacy of exclusive breast-feeding for providing optimum growth through 6 months of age.

Age Factors↗
PubMed1983

Emergency drills in a pediatric residency training program.

A variety of common pediatric emergencies were created in anesthetized cats to provide pediatric house officers and practicing physicians with an opportunity to refine diagnostic and management skills in a controlled environment under supervision. We describe the format of the animal model drill, outline protocols for stimulating pediatric critical care emergencies, and present preliminary evaluation data from a continuing medical education workshop and from house staff drills regarding the efficacy of the program.

Animals↗
PubMed1983

A controlled trial of a physical fitness program for fifth grade students.

The relative effectiveness of a structured physical fitness program was compared with that of the customary organized activities for fifth grade students. The level of fitness was compared at the beginning and end of the nine-month academic year as well as after the three-month summer recess during which time no structured program was offered. The experimental group showed significant improvement over the control group in flexibility, strength and endurance during the school year; part of that improvement was maintained over the summer months; the physical fitness program had a positive influence on the general activity level of the students and was adopted by nine of the other 10 classrooms in the experimental school.

Child↗
PubMed1983

A survey of physician consultations in an urban school district.

A survey of physician encounters was conducted in a large, urban school district following the institution of consultative, rather than full-time, school physician services. Review of the encounter data over a six-month period revealed that: (a) the majority of consultations related to the problems of individual children; (b) there was a high prevalence of behavioral and psychosocial issues among the problems addressed; and (c) physicians were prominently involved in cross-disciplinary interactions. The survey provides an analysis of physician utilization under an emerging model of school health services in which physicians serve as consultant members of a medical and educational team.

Adolescent↗
PubMed1982

Successive factor VIII doses for a haemophiliac undergoing major surgery calculated on a micro-computer.

Doses of factor VIII to be infused into a haemophiliac undergoing major surgery were calculated on a micro-computer. The degree to which the particular patient responded to infused factor VIII and the rate at which it decayed were estimated by two pre-operative experiments. Plasma levels of factor VIII were predicted over fourteen days during which time the patient was infused with 53,000 iu. A continuous plot of predicted values with time was displayed on a video monitor. The predicted values showed good agreement with assay results.

Adult↗
PubMed1981

Shigella sepsis.

It is generally believed that bacteremia rarely occurs with enteric Shigella infections. During a five-year period, 110 children were admitted to the University Hospital of the Arizona Health Sciences Center, Tucson, with Shigella enteritis. Eight (7%) had Shigella bacteremia/septicemia, and four of the eight died. An analysis of these patients and their course disclosed clinical characteristics that were of potential prognostic importance. Some of these indicators are identifiable early and hence could be useful in management. The patients at greatest risk were afebrile; 10% or more dehydrated; malnourished, with a low serum albumin level; infected with ampicillin-resistant strains; had leukopenia during the course of the illness; and had persistent watery hemoglobin-positive stools.

Child, Preschool↗
PubMed1979

A comparison of growth: Spanish-surnamed with non-Spanish-surnamed children.

Weight, height, and head circumference measurements of 4,167 Spanish-surnamed school-aged children were compared with similar data from 2,322 non-Spanish surnamed children who resided in the same Denver, Colorado neighborhoods. These data were also compared with data from six other studies. Both male and female Spanish-surnamed children were found to weigh less, be shorter, and have smaller head circumferences than non-Spanish-surnamed children living in the same Denver neighborhoods. The sizes of the children in these two populations residing in lower and lower-middle class neighborhoods were closer to each other than to the sizes of children from middle and upper-middle socioeconomic classes as measured in previous studies or to the sizes of children in the recently published cross-sectional National Center for Health Statistics study. Such comparisons suggest that growth retardation is more a reflection of socioeconomic factors than of ethnic-genetic factors.

Adolescent↗
PubMed1979

Change in worker/nonworker ratios for women.

Effects of age, birth year, and observation year on work behavior are estimated by minimum logit chi-square regression, using data from Current Population Surveys. Most of the observation-year effect is captured by indicators of the business cycle. Further, a model which permits the cycle effects to vary by age is preferred over any additive model. The ratio for young women is most depressed relative to that for older women when times are "good".

Age Factors↗
PubMed1976

Iron and blood donation. Evaluation of a kit method for routine use in a blood transfusion service.

Manifest iron-deficiency anaemia is preceded by a latent stage in which normal haemoglobin levels coexist with low serum iron levels. Regular blood donation involves the removal of significant amounts of iron, and in susceptible donors, may aggravate iron deficiency. It is important for a blood transfusion service to be able to identify these susceptible donors. A commercial kit for the determination of serum iron levels was evaluated and found suitable for introduction as a routine screening test for a transfusion service. A survey of serum iron levels of 200 blood donors showed that 12 1/2% had levels below the normal reference range.

Anemia, Hypochromic↗