Biomedical subjects

R L Norris

Publications and source records attributed to R L Norris.

9 recordsLinked to original sources

PubMed1992

The influence of vancomycin concentration and the pH of plasma on vancomycin protein binding.

A review of numerous studies of the protein binding of vancomycin suggests major discrepancies among their results. The reported percent protein binding of vancomycin varies from 0% to 98%. The influence of pH and concentration on the protein binding of vancomycin was investigated in this study. There was a significant difference (p < 0.001) in percent protein binding in vancomycin-spiked plasma samples across the pH range of 7.0-8.0. There was no significant difference (p > 0.05) in percent protein binding in vancomycin-spiked plasma samples across the concentration range of 2-80 mg/L. It is likely that some of the variation reported to date may be due to a lack of control of pH during the measurement of protein binding of vancomycin.

Blood Proteins↗

PubMed1992

Ketorolac for sickle cell vaso-occlusive crisis pain in the emergency department: lack of a narcotic-sparing effect.

STUDY OBJECTIVE: To determine if a single dose of intramuscular ketorolac given on presentation to the emergency department has a narcotic-sparing effect in adult patients with sickle cell vaso-occlusive crisis pain. DESIGN: A prospective, randomized, single-dose, double-blind study. SETTING: ED of a university hospital and an affiliated county hospital. TYPE OF PARTICIPANTS: Eighteen adult patients who presented to the ED with sickle cell crisis pain a total of 24 times. INTERVENTIONS: Patients were randomized to receive either ketorolac 60 mg IM or placebo on presentation to the ED. Subjects were administered meperidine on presentation and then received a standardized dose of meperidine every 30 minutes during the four-hour observation period based on the severity of pain. MEASUREMENTS AND MAIN RESULTS: The 12 subjects in the ketorolac group received an average of 231 +/- 92 mg meperidine, whereas the 12 subjects in the placebo group received an average meperidine dose of 250 +/- 85 mg (P = .61). CONCLUSION: The use of intramuscular ketorolac did not lead to a clinically significant reduction in the requirement for narcotics during the four-hour ED treatment period.

Acute Disease↗

PubMed1992

Local anesthetics.

Emergency physicians often rely on the use of local anesthetic agents to relieve patient discomfort, and research continues in an effort to develop new agents with improved anesthetic qualities. Eventually, a nontoxic, rapidly acting agent may become available that could provide profound anesthesia of long duration when applied topically to intact skin or wounds. Until the "perfect" agent is developed, physicians can help the patient by making knowledgeable choices regarding local anesthetic techniques. By choosing topical agents when appropriate and buffering agents to be infiltrated, using courteous techniques of injection, and being cognizant of potential adverse reactions, the physician can turn a potentially unpleasant and frightening situation for the patient into a positive experience that promotes satisfaction and cooperation.

Anesthetics, Local↗

PubMed1989

Apparent coral snake envenomation in a patient without visible fang marks.

Envenomation by the North American coral snake is an uncommon entity in the United States. In most cases fang marks will be present, although they may be quite small and difficult to see. The case of a young man who demonstrated evidence of envenomation following the bite of a Texas coral snake (Micrurus fulvius tenere), despite the absence of any apparent fang marks on close examination, is reported. The problems associated with coral snake envenomation in terms of diagnosis and management are reviewed.

Adult↗

PubMed1989

Preliminary observations on the effects of hyperbaric oxygen therapy on western diamondback rattlesnake (Crotalus atrox) venom poisoning in the rabbit model.

Intermittent hyperbaric oxygen therapy has been shown to reduce skeletal muscle necrosis in a compartment syndrome animal model. To study whether intermittent exposure to hyperbaric oxygen augments antivenin therapy in reducing muscle necrosis, we injected sublethal doses of Western Diamondback rattlesnake (Crotalus atrox) venom intramuscularly into the hind legs of New Zealand White rabbits. In this pilot study, the animals were divided into three treatment groups. The first group received one vial of antivenin intravenously, the second group received one vial of antivenin intravenously plus three hyperbaric oxygen treatments, and the third group received no treatments. There were no statistically significant differences among the groups. These preliminary observations suggest that muscle necrosis secondary to Crotalus atrox venom poisoning is not significantly altered either by Antivenin [Crotalidae] Polyvalent at the dose level we used or in combination with intermittent hyperbaric oxygen treatments in this rabbit model.

Animals↗

PubMed1989

Deep vein thrombosis in an adolescent.

We report an unusual case of deep vein thrombosis following minor trauma in an adolescent who presented with a swollen, tender, lower extremity. Work-up consisted of a venogram which demonstrated occlusion of the deep venous system in the proximal leg. The patient was hospitalized for intravenous heparin followed by oral anticoagulation therapy. The problem of deep venous thrombosis in adolescents and the approach to diagnosis are discussed.

Adolescent↗

PubMed1988

A modified assay for cyclosporin in blood using solid-phase extraction with high-performance liquid chromatography.

A modified procedure for measuring cyclosporin in whole blood by high-performance liquid chromatography is described and evaluated for clinical use. Sample preparation uses solid-phase extraction cartridges that can be reused. Life of the reverse-phase analytical column exceeds 1,000 injections at 70 degrees C. Cyclosporins A and D (internal standard) elute after 5.6 and 7.6 min, respectively. Calibration plots are linear from 50 ng/ml to at least 2,000 ng/ml. Within-day and between-day imprecision is less than 9% (coefficient of variation). Minimum measurable concentration is 50 ng/ml.

Chromatography, High Pressure Liquid↗

PubMed1987

Temelastine does not affect theophylline pharmacokinetics in normal subjects.

The pharmacokinetics of theophylline (i.v. aminophylline 250 mg) were studied in a balanced, double-blind crossover following the administration of oral temelastine (100 mg) or placebo, twice daily for 7 days, to 10 normal volunteers. Comparison of volumes of distribution, elimination rate constants, elimination half-lives and areas under the plasma concentration-time curve indicated that temelastine had no significant effect on theophylline pharmacokinetics.

Adult↗

PubMed1986

Assessment of a two-step high-performance liquid chromatographic assay using dual-wavelength ultraviolet monitoring for 25-hydroxyergocalciferol and 25-hydroxycholecalciferol in human serum or plasma.

The technique of dual-wavelength monitoring was used to verify the purity of high-performance liquid chromatographic (HPLC) peaks quantified as 25-hydroxyergocalciferol and 25-hydroxycholecalciferol. The data obtained show the need for a second HPLC step prior to quantitation. Potential inaccuracy arising from inadvertent collection of radio-labelled decomposition products was assessed. Between-day coefficients of variation were 7.3, 5.0 and 3.6%, respectively for 11.3 (n = 12), 17.1 (n = 14), and 32.9 (n = 8) ng/ml of 25-hydroxycholecalciferol. For 25-hydroxyergocalciferol, these values were 6.4 and 3.8% for 11.1 (n = 12) and 20.1 (n = 8) ng/ml concentrations, respectively. Comparison of total 25-hydroxycalciferol with a competitive protein binding assay was made. The comparison produced a correlation coefficient (r) of 0.94 and a relationship of y = 1.03x + 3.3. Four of the samples contained more than 10 ng/ml of 25-hydroxyergocalciferol and the results are consistent with the reported 100% cross-reactivity of the competitive binding protein method for 25-hydroxyergocalciferol and 25-hydroxycholecalciferol. A simple regeneration procedure is also described which enables Sep-Pak C18 cartridges to be reused up to eighteen times. Samples may be stored at -18 degrees C for upto several months before assay and either serum or plasma may be used.

25-Hydroxyvitamin D 2↗