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Biomedical subjects

B Doyle

Publications and source records attributed to B Doyle.

At least 19 recordsLinked to original sources

Dynamics of the 16O(e, e'p) reaction at high missing energies.

We measured the cross section and response functions for the quasielastic 16O(e,e'p) reaction for missing energies 25< or =E(m)< or =120 MeV at missing momenta P(m)< or =340 MeV/c. For 25<E(m)<50 MeV and P(m) approximately 60 MeV/c, the reaction is dominated by a single 1s(1/2) proton knockout. At larger P(m), the single-particle aspects are increasingly masked by more complicated processes. Calculations which include pion exchange currents, isobar currents, and short-range correlations account for the shape and the transversity, but for only half of the magnitude of the measured cross section.

Journal Article↗

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Canada↗

Thrombocytopenia.

Determining the true cause of thrombocytopenia is a difficult and challenging clinical problem. Thrombocytopenia results from various causes, but ultimately occurs when platelets are destroyed, sequestered in the body, or not produced. The differential diagnosis of thrombocytopenia is extensive and complex, and there is a significant overlap among disorders. The advanced practice nurse must take a holistic approach to the patient, eliciting a detailed history and performing a comprehensive physical examination with special emphasis on the skin, abdominal, lymph node and neurologic consideration.

Adult↗

Tissue pressures in pyogenic flexor tenosynovitis of the finger. Compartment syndrome and its management.

We investigated 14 patients with pyogenic flexor tenosynovitis for increased tissue pressures in involved digits. All showed raised pressures, in eight to 30 mmHg or more. These levels are consistent with a compartment syndrome. We describe the results of a modified operative technique which includes irrigation of the sheath and the leaving open of a lateral incision. This also allows early active mobilisation of the finger and has given satisfactory early results.

Adolescent↗

Differences in participation in experimental drug trials among persons with AIDS.

To measure participation in experimental drug trials among persons with acquired immunodeficiency syndrome (AIDS), we interviewed 4,604 persons at least 18 years of age who were reported to have AIDS to 11 state and city health departments in the United States. Ten percent reported that they were currently in a trial. Current enrollment differed significantly (p < 0.05) by race/ethnicity (blacks, 5%; whites, 14%; Hispanics, 15%), gender (women, 7%; men, 11%), exposure mode (injection drug use, 5%, men who have sex with men, 14%), annual household income (< $10,000, 8%, > or = $10,000, 14%), education (< 12 years, 6%; > or = 12 years, 12%), health care (no regular care, 1%, public care, 8%; private care, 17%), and time since AIDS diagnosis (< or = 6 months, 9%; > 6 months, 12%). Adjusting for all factors and time since AIDS diagnosis, blacks (adjusted odds ratio [AOR] = 0.35, 95% confidence interval [CI] 0.26, 0.47), persons with less than 12 years of education (AOR = 0.71, CI 0.53, 0.96), and those without regular health care (AOR = 0.24, CI 0.10, 0.61) remained less likely to be in a trial. Blacks, those with less than 12 years of education, and persons without regular health care were less likely than other persons with AIDS to be currently enrolled in AIDS trials. To increase enrollment of these persons, researchers must address barriers to participation for these groups.

Acquired Immunodeficiency Syndrome↗

HIV testing patterns: where, why, and when were persons with AIDS tested for HIV?

OBJECTIVE: To describe the location of, primary reason for, and time between the first positive HIV test and AIDS diagnosis in a sample of persons with newly diagnosed AIDS. DESIGN: Interviews supplementing information routinely collected through AIDS case reporting. SETTING: Eleven US states and cities. PATIENTS: Persons with AIDS (2441) diagnosed between January 1990 and December 1992. MAIN OUTCOME MEASURES: Location of first positive HIV test, primary reason for testing, and time interval between first positive HIV test and AIDS diagnosis. RESULTS: Overall, persons were tested late in their course of HIV infection: 36% were tested for HIV within 2 months and 51% within 1 year of their AIDS diagnosis. Sixty-five per cent were HIV-tested in acute health-care settings: 33% in hospitals, 28% in physicians' offices, and 4% in emergency departments. Testing during hospitalization was most common among injecting drug users (43%) and persons infected through heterosexual contact (50%). Persons primarily sought HIV testing because of illness (58%); other reasons included being in a known risk group (13%) and having had a known HIV-infected sex partner (8%). Testing because of being in a known risk group was least common among persons infected through heterosexual contact (1%). Among persons in these exposure categories, testing differed by race/ethnicity. CONCLUSION: Most persons with AIDS were tested relatively late in their course of HIV infection, in acute health-care settings, and because of illness. Not knowing one's serostatus precludes early medical intervention and may increase transmission.

AIDS Serodiagnosis↗

Stimulus-response compatibility in a small sample of cerebral palsied adults.

Stimulus-response compatibility refers to the correspondence between a sensory event and the motor response which it specifies. A discrete aimed movement task with two conditions of stimulus-response compatibility tested whether higher compatibility would decrease the reaction time of 5 subjects with normal movement and 6 subjects with cerebral palsy. A board with 3 distances (13.5, 28.0, 40.5 cm) along each of 3 rays (45 degrees, 90 degrees, 135 degrees) provided 9 target sites for a detachable leaf switch. A light on the switch was turned off or on for the low or high compatibility condition. The independent variables were the Index of Difficulty, target position and compatibility. The dependent variables were reaction time and movement time. The reaction times for both groups were less during the high compatibility condition than during the low compatibility condition as shown by a t test for differences between means. Multiple regression analyses showed that reaction time of the normal group was a positive linear function of compatibility and movement time was a positive linear function of the Index of Difficulty for both groups and of position for the normal group, 3 normal subjects and 2 cerebral palsied subjects. There were indications of ballistic rather than aimed movements. The results are discussed with regard to the role of visual fixation in aimed movement, the similarities between groups in conformance to Fitts' Law and differences between groups in reaction and movement times.

Adult↗

The effect of simulated fracture-angulations of the tibia on cartilage pressures in the knee joint.

The effects of angular deformities of the tibia on the contact areas and pressures on cartilage in the knee were measured with use of pressure-sensitive film. Six cadaver knees were mounted in a test-frame, such that the offset and tilt of the knee relative to the load-axis simulated that due to angular deformities of the tibia of 5, 10, 15, or 20 degrees of varus or valgus at the levels of the proximal, middle, and distal thirds. Angulation had little effect on the contact area. The change in pressure was least for fractures of the distal third and greatest for fractures of the proximal third. For example, a 20-degree angulation of the distal third increased the maximum contact pressure by an average of 26 per cent in the compartment toward the load-axis and reduced it by 32 per cent in the opposite compartment. With an angulation of 20 degrees at the level of the proximal third of the tibia, the increase in pressure averaged 106 per cent and the decrease averaged 89 per cent. The changes in pressure with fractures at the middle third were between these extremes.

Biomechanical Phenomena↗

The metabolism of ellagic acid in the rat.

1. Following oral administration of ellagic acid to the rat, 10% of the dose was excreted as 3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one in urine and faeces. A second metabolite was detected in urine and faeces but not identified. Both metabolites were of microfloral origin, as their formation was not observed in germ-free rats but was demonstrated when ellagic acid was incubated in vitro with micro-organisms from rat gastro-intestinal tract. 2. Following intraperitoneal, but not oral, administration of ellagic acid, a third metabolite was detected in urine. 3. Unchanged ellagic acid was not detected in faeces or urine of any normal rat examined, but small amounts were detected in the faeces of germ-free animals. 4. Following oral administration of ellagic acid, two conjugates of 3,8-dihydroxy-6H-dibenzo[b,d]pyran-6-one were detected in bile, whereas intraperitoneal administration resulted in the biliary excretion of three conjugates of an unidentified metabolite.

Administration, Oral↗

Pulmonary artery pressure and lung water during extracorporeal circulation in experimental pulmonary insufficiency.

Use of the membrane oxggenator has been advocated in the management of severe respiratory insufficiency. We have compared this method to conventional therapy in an experimental model in which 23 dogs were subjected to aspiration with 0.1 N HC1 and 18 were supported with a volume respirator and positive end-expiratory pressure or placed on partial bypass using a membrane oxygenator for 12 to 24 hours. Adequate oxygenation (POX greater than 100 mm Hg) was achieved with the membrane oxygenator. The increase in lung weight during conventional therapy was significantly greater than during membrane oxygenator support. Extracorporeal support during recovery from severe pulmonary injury allows pulmonary artery pressure to be controlled and reduces the expected increase in lung water.

Animals↗