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Biomedical subjects

P Somerville

Publications and source records attributed to P Somerville.

7 recordsLinked to original sources
PubMed1994

A study on the reliability of dipstick urinalysis.

The objective of this study is to determine the reliability of the Ames automated method as a screening procedure for the detection of red blood cells and leukocytes. 5486 urines were analyzed by an automated dipstick technique. 3127 urines were completely negative on the stick and 2359 showed a positive finding. All 2359 dipstick positive urines and 456 of the 3127 dipstick negative urines (total of 2815) were read blindly by one of two nephrologists working on different days, 1743 by M. K. and 1072 by P. S. Red cells, leukocytes and casts were enumerated per high power field and compared to the dipstick findings. Urines that were negative by dipstick for protein, blood leukocytes, nitrites, glucose and ketones were generally negative on microscopic examination, with only 5.3% having any abnormality. Urines positive for one or more of these findings correlated poorly with the microscopic findings due to the number of false positive and false negative dipsticks for red cells and leukocytes. Sensitivities were 75.3% and 81.0% and specificities were 88.6% and 64.3%, for red cell and leukocytes, respectively. Increasing the dipstick cutoff point improved sensitivity but lowered specificity. Urines positive for glucose and ketones had lower sensitivities for the detection of leukocytes, but not urines positive for protein. Microscopic examination should be done on dipstick abnormal urines. This may not be necessary for negative urines unless specifically indicated for clinical reasons. Urines positive for ketones or glucose should be screened systematically since they give a larger proportion of false negatives for leukocytes.

Female↗
PubMed1993

Asymmetrical hypersensitivity to bovine collagen.

We report a unique patient with true asymmetrical hypersensitivity to bovine collagen. Hypersensitivity is the development of an inflammatory response at a treatment site after a negative skin test. She developed an inflammatory response in only one of two simultaneously injected sites. About 1.5% of patients with a negative skin test have a hypersensitivity reaction consisting of firmness, erythema, and swelling. The signs and symptoms generally resolve spontaneously in a few months.

Adult↗
PubMed1992

Can experienced clinicians predict the outcome of lupus nephritis?

The ability of four experienced clinicians to predict short-term outcome (serum creatinine level at 1 year) and long-term outcome (renal insufficiency) was evaluated in 87 patients with lupus nephritis. The correlational agreement and the accuracy of their predictions were contrasted with the actual outcomes observed and with statistically generated prognostic regression models. In contrast to previously published data, all four clinicians predicted both short-term outcomes (P < 0.001) and long-term outcomes (P < 0.02) well. The clinicians' predictions approximated that of a statistically generated computer model for both agreement and accuracy for renal function at 1 year. The four clinicians identified nearly identical clinical variables as important in determining prognosis. Provision of biopsy data to the clinicians improved short-term and long-term prediction slightly. The value of the statistical models was 'validated' by demonstrating that three of the four clinical variables identified by the models, but not by the clinicians, could enhance clinical prediction (P < 0.05). In addition, the extent of tubulo-interstitial involvement on biopsy, a predictor that has recently received increased attention, could improve the long-term clinical predictions of all four clinicians (P < 0.05).

Adolescent↗
PubMed1988

Circulating form of beta-2-microglobulin in dialysis patients.

The circulating profile of beta-2-microglobulin (beta 2M) was determined in 8 end-stage renal disease patients on long-term dialysis (6 on hemodialysis, 2 on CAPD) by measuring beta 2M in different fraction after molecular sieve separation of their sera. Four patients had carpal tunnel syndrome with demonstrated amyloid in excised wrist tissues of which 2 were positive for beta 2M. In all patients despite very high blood levels (34.3-63.1 mg/l), beta 2M eluted exclusively as a single peak in the molecular weight region of about 12,000 daltons on a calibrated Sephacryl S-200 column. Recoveries from within the peak accounted for 96% of the applied beta 2M serum concentrations. These results were confirmed by molecular sieve separation of the enriched beta 2M-containing fractions by high-pressure liquid chromatography. We conclude that immunoreactive beta 2M in dialysis patients circulates as an intact monomer without evidence for the formation of aggregates or fragments. The pathogenesis of tissue deposition of this low-molecular-weight protein and its polymerisation to form a specific amyloid remains to be defined.

Adult↗