Biomedical subjects

R A Watson

Publications and source records attributed to R A Watson.

68 records · Page 4Linked to original sources

PubMed1979

Continuous-flow fluoroimmunoassay of serum gentamicin, with automatic sample blank correction.

We describe the continuous-flow automation of a quenching fluoroimmunoassay for determination of the antibiotic gentamicin in serum. In the flow system, sample is mixed with fluorescein-labeled gentamicin, followed by antiserum, and after a short incubation the fluorescence is measured. The intrinsic blank signal of each sample is corrected for during its single passage through the system by pumping antiserum discontinuously, so as to divide the final stream into sections corresponding to conventional separate assay and blank mixtures. Analyses time for each sample is 6 min, and 20 samples can be run per hour. Sensitivity, precision, and accuracy are adequate for clinical purposes, and assays of patients' samples correlate satisfactorily with the results of manual quenching and polarization fluoroimmunoassays, and plate diffusion bioassay.

Fluorescence↗

PubMed1977

Estimation of serum gentamicin by quenching fluoroimmunoassay.

A new type of non-isotopic immunoassay, applied to the determination of serum gentamicin, is reported. The method is based on partial quenching of fluorescence observed when fluorescein-labelled gentamicin is bound by anti-gentamicin serum. The fluorescence intensity of the labelled gentamicin in an unseparated immunoassay incubation mixture therefore serves to indicate the extent of binding, which is related to the amount of competing unlabelled gentamicin present. Precision and accuracy are shown to be similar to those of the best existing methods for gentamicin, while the new assay is more rapid and technically simpler, and avoids the use of expensive radio-chemicals with their attendant health hazard. Assays of patient samples correlate with established bioassay and polarisation fluoroimmunoassay methods.

Evaluation Studies as Topic↗

PubMed1976

Polarisation fluoroimmunoassay of gentamicin.

A polarisation fluoroimmunoassay has been developed for the routine determination of gentamicin levels in serum. The method employs fluorescein-labelled gentamicin which is easily, reproducibly and economically prepared and has excellent shelf-life. The assay is fast (minimum incubation time 2 min) and requires 1.25 mul of serum. There is no separation step prior to readout of results. Recovery experiments reveal no serum effects. Intra- and inter-assay coefficients of variation are of the order of 10% or less. Estimations of gentamicin levels in patient serum samples correlate closely with those obtained by bioassay (r = 0.93) and radioimmunoassy (r = 0.97).

Biological Assay↗

PubMed1975

Torsion of spermatic cord in neonate.

Torsion of the spermatic cord in the neonate should no longer be considered a clinical rarity. Effectual diagnosis is totally dependent on prompt detection of an asymptomatic, irreducible scrotal swelling that fails to transilluminate. Immediate surgical exploration is indicated. Detorsion and careful inspection for signs of circulatory return should be undertaken in every case. Frankly necrotic testes should probably be removed, but conservation of testicular tissue is otherwise strongly recommended, even in the borderline cases. After detorsion testis must be firmly fixed in proper position. Prophylactic contralateral orchiopexy appears to be advisable, unless a congenital hydrocele intervenes. Most importantly, to avert the grim prognosis this condition bears, we must continually alert our colleagues responsible for neonatal care to the possibility of torsion of the spermatic cord in the immediate postpartum examination of every newborn male infant.

Diagnosis, Differential↗

PubMed1974