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Biomedical subjects

J Nightingale

Publications and source records attributed to J Nightingale.

7 recordsLinked to original sources
PubMed1991

The design of a two-phase radiolabelled meal for gastric emptying studies.

A meal intended for use in gastric emptying studies must be highly reproducible, must provide a normal physiological stimulus in terms of bulk, calorie content and composition and must employ stable radiotracers which accurately reflect in their biodistribution, the fate of the two phases. This is particularly important in a field, such as gastric emptying, where so many variables may influence the results. A conventional pancake and orange juice were chosen as suitable vehicles for the solid and liquid phases. 111In-labelled resin beads were used as the solid-phase marker and a variety of 99Tcm-labelled radiopharmaceuticals including pertechnetate, DTPA and colloid forms were investigated as liquid-phase markers. Prior to administration to patients, the stability of the phases and their interactions in vitro were investigated. The use of 99Tcm-DTPA resulted in a loss of 111In from solid to liquid phase. All non-colloidal markers exhibited a tendency for adsorption onto solid phase. Colloidal markers including rhenium and antimony sulphide colloids showed the truest delineation of the liquid phase.

Drinking↗
PubMed1989

Coping with patients' problem drinking.

Confronting patients appropriately is a difficult skill to master. The practitioner must first overcome his own inherent biases and feelings of discomfort before tackling the patient on threatening issues. This problem is compounded by delay when a patient has seen his GP for a number of years before a review of the notes reveals the hitherto unsuspected diagnosis.

Adult↗
PubMed1987

Effect of phenytoin on serum disopyramide concentrations.

The effects of phenytoin on serum disopyramide concentrations in 10 volunteers were studied. Leading to the study was the case of a 59-year-old man who received phenytoin and disopyramide and who required unusually high doses of disopyramide and an unusually high serum concentration of this drug to control his ventricular tachycardia. Ten healthy men 23-36 years of age each received a single oral dose of disopyramide phosphate 300 mg. Periodic blood samples were obtained for 24 hours after the dose. On day 2, the subjects began a 13-day course of oral phenytoin sodium 300 mg/day, and on day 14 each again received a single oral dose of disopyramide, after which blood samples were obtained. Serum disopyramide concentrations were determined by enzyme-mediated immunoassay and gas chromatography and serum phenytoin concentrations by fluorescence polarization immunoassay. Pharmacokinetic values before and after phenytoin administration were calculated. The mean area under the serum concentration-time curve for disopyramide and the disopyramide half-life and elimination rate constant were significantly different before and after phenytoin treatment. The maximum serum disopyramide concentrations were not significantly different. After phenytoin therapy, subjective complaints of anticholinergic effects increased in number and severity. An interaction between disopyramide and phenytoin appears to exist and to be caused by an increase in the hepatic metabolism of disopyramide.(ABSTRACT TRUNCATED AT 250 WORDS)

Disopyramide↗
PubMed1987

Clinical limitations of in vitro testing of microorganism susceptibility.

General concepts in evaluating the clinical importance of discrepancies between in vitro susceptibility tests of microorganisms and in vivo results are reviewed, and four problematic antibacterial-bacterial combinations are discussed. The three most common in vitro testing systems--agar disk diffusion, agar dilution, and broth dilution--are designed to detect the minimum inhibitory concentration (MIC) of an antimicrobial agent. However, agar and broth systems cannot include all of the biologic variables found within the human body. Factors affecting the reliability of in vitro testing systems include the limitations in interpreting MIC data, because in vitro test conditions cannot duplicate the host environment; the variability of testing media (e.g., acidic versus alkaline, differences in cation content); and the limiting effect of protein binding on an antimicrobial agent. In vitro testing systems do not consider the pharmacokinetics of the antimicrobial agent or the postantibiotic effect, whereby microbial growth is suppressed even when the antibiotic concentration falls below the MIC. The variability in drug distribution to infection sites within the body is also not considered. The following antimicrobial agent-bacterial combinations present specific problems to the clinician: trimethoprim-sulfamethoxazole and Group D enterococcus, cephalosporins and methicillin-resistant Staphylococcus aureus, aminoglycosides and Staph. aureus, and aminoglycosides and Pseudomonas aeruginosa. Despite the limitations of currently available systems, in vitro testing of the susceptibility of microorganisms can be an invaluable tool in selecting antimicrobial therapy when it is used in conjunction with data regarding the clinical course of the infected patient.

Aminoglycosides↗