Biomedical subjects
R J Roberts
Publications and source records attributed to R J Roberts.
Effects of minority status on facial recognition and naming performance.
Found performances on two tests of higher cerebral function, a facial recognition test and a naming test in an aphasia examination, to be influenced differentially by minority status (N = 94). Performance on the facial recognition test was relatively free of racial bias for the purposes of clinical assessment, but this was not the case for visual naming. In fact, straightforward application of the standard criteria for the naming test would have resulted in classification of 22% of a sample of urban black control patients as defective. Revised normative standards are presented for use in this segment of the referral population.
A playroom observational procedure for assessing hyperactive boys.
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Restriction and modification enzymes and their recognition sequences.
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Forearm blood flow responding prior to voluntary isometric contraction.
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Hyperoxia effects on pulmonary pressure: volume characteristics and lavage surfactant phospholipid in the newborn rabbit.
The effect of hyperoxia (greater than 95%) on surfactant phospholipid recovered by lavage and pulmonary pressure:volume characteristics was studied in rabbits exposed from birth through 4 days of life. Decreased surfactant phospholipid (microgram/mg dry lung weight) in the airways was observed as early as 6 h and persisted through 96 h of life in hyperoxia-exposed animals. The composition of lavage phospholipids and fatty acid profile of phosphatidylcholine was not altered by hyperoxia. Pressure:volume analysis revealed a decrease in maximum lung distensibility (V30, volume at 30 cm pressure) at 48 and 96 h and a decrease in inflation compliance (P30i, pressure on inflation to 30% V30) at 48 h of life in newborn pups exposed to hyperoxia. Pressure:volume changes in both male and female newborns were observed with hyperoxia exposure. However, only female pups exhibited a decrease in lavage phospholipid content as measured at 48 h. These data suggest that the newborn rabbit surfactant system is susceptible to oxygen toxicity. In addition to age-related differences, sex differences may exist with regard to susceptibility to hyperoxia. Subtle alterations in the surfactant system at this critical time of rapid lung development could have long lasting effects on lung function.
Acute thallium poisoning in a 3-year-old child. A case report.
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Vitamin E inhibition of the effects of hyperoxia on the pulmonary surfactant system of the newborn rabbit.
The effects of vitamin E on the neonatal surfactant system were studied in rabbits exposed to air or hyperoxia (greater than 95%) from birth through 48 h of life. Hyperoxia exposure resulted in lung lavage phospholipid content which reached only 74% of air-exposed controls, and static pressure:volume observations of decreased maximum distensibility and altered compliance. Treatment with vitamin E (100 mg/kg of dl-alpha-tocopherol S.Q.) at 1 and 24 h of life was shown to completely abolish these effects of hyperoxia. Morphometrically determined alterations in epithelial cell composition and erythrocyte-contaminated air spaces resulting from hyperoxia exposure were also absent in pups treated with vitamin E. These findings suggest that early vitamin E treatment in vitamin E-deprived newborns prevents hyperoxia-associated compromise to the pulmonary surfactant system and selected other aspects of oxygen-induced lung injury in the neonate.
The role of occlusion in reducing multistability in moving point-light displays.
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Effects of intravenous delivery systems on infused red blood cells.
The effects of various intravenous delivery systems on the integrity of infused red blood cells (RBCs) were studied. Using a factorial design, whole blood and packed RBCs were infused through i.v. delivery systems employing various combinations of i.v. tubing diameter and length, needle gauge, infusion rate (5 and 50 ml/hr), type of infusion pump (piston, diaphragm, or peristaltic operation), and type of blood product. The age and temperature of the blood filter used were held constant. A 5-ml sample of the blood product obtained during each experimental run was analyzed for plasma free-hemoglobin to assess the degree of hemolysis. Osmotic fragility of the RBCs was evaluated by measuring the percentage of hemolysis in the blood products in various concentrations of sodium chloride solution. Type of blood product and i.v. pump were the only variables significantly influencing RBC hemolysis. In both blood products, a greater degree of hemolysis occurred with the peristaltic-type pump than with the other types of pumps. In packed RBCs, the diaphragm-type pump produced greater hemolysis than the piston-type pump, but hemolysis was similar in whole-blood samples. Regardless of the type of pump, more hemolysis occurred in whole blood at the 5-ml/hr infusion rate than at the 50-ml/hr rate, but the converse was true in packed RBCs. Samples of both blood products were less osmotically fragile than their respective controls at sodium chloride concentrations ranging from 0.30 to 0.50%.(ABSTRACT TRUNCATED AT 250 WORDS)
Aspergillomycosis in intensively cultured tilapia from Kenya.
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Restriction and modification enzymes and their recognition sequences.
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Method for the isolation of Aspergillus species pathogens of fish from clinical materials.
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Use of hemoperfusion for treatment of theophylline intoxication.
We review our experience in the management of patients with plasma theophylline concentrations of 30 micrograms/ml or greater. Over a two-and-a-half-year period, 22 patients (Group 1) had plasma theophylline concentrations of 37 +/- 1 micrograms/ml (mean +/- SE) and experienced no severe toxicity (i.e., ventricular extrasystoles or tachycardia, seizures, cardiovascular collapse, or death). Six patients (Group 2) took overdoses of theophylline (92 +/- 12 micrograms/ml) and one died. Eight patients (Group 3) were iatrogenically intoxicated (48 +/- 6 micrograms/ml) and three died. Six patients from Groups 2 and 3 underwent hemoperfusion and did well, except for one patient, in whom seizures developed before hemoperfusion was initiated. We conclude from this experience that charcoal hemoperfusion is a useful procedure for the treatment of theophylline intoxication because of: (1) the serious morbidity and mortality of theophylline intoxication, (2) the prevention of complications with hemoperfusion, and (3) the relative safety of the procedure. We provide tentative guidelines for the initiation of hemoperfusion for the treatment of theophylline intoxication.
Host factors influencing the response to antimicrobial agents.
When the desired clinical response to an antibiotic therapeutic regimen is not achieved, despite appropriate antibiotic selection and organism sensitivity, the clinician must be aware that several host factors exist that may influence the outcome. Examples of the influence of host-related factors on drug disposition have been briefly reviewed in this article. It should be noted, however, that further investigation is needed to determine whether these factors truly exert a significant influence on the outcome of antibiotic utilization.
Information content of the adenovirus-2 genome.
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