Liquid-chromatographic determination of vancomycin evaluated and improved.
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Chromatography, High Pressure Liquid↗
Biomedical subjects
P R Finley
Publications and source records attributed to P R Finley.
Re: Myocardial contusion following nonfatal blunt chest trauma.
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Contusions↗
Lidocaine elimination: effects of metoprolol and of propranolol.
The effects of administration of metoprolol and propranolol on lidocaine elimination were studied in six healthy young men who did not smoke. Each received three single intravenous doses of lidocaine (2.5 to 3.0 mg/kg injected over 10 min): one alone, one after 1 day pretreatment with propranolol (40 mg orally every 6 hr), and one after 1 day pretreatment with metoprolol (50 mg orally every 6 hr). Lidocaine clearance was 0.88 +/- 0.28 l X hr-1 X kg-1 before beta blockade, 0.61 +/- 0.20 l X hr-1 X kg-1 during metoprolol dosing, and 0.47 +/- 0.16 l X hr-1 X kg-1 during propranolol dosing. There was no correlation between the change in lidocaine elimination and the steady-state concentrations of metoprolol or propranolol, nor between the change in lidocaine clearance and the change in resting heart rate produced by either beta blocker. Metoprolol and propranolol reduce lidocaine elimination significantly.
Adult↗
Phagocytic, lambda light chain, plasma cell myeloma.
A case of phagocytic, lambda light chain, plasma cell myeloma was characterized by its clinical, morphologic, cytochemical, immunologic, and cell kinetic features. A 40-year-old man presented with Coombs-negative hemolytic anemia, hepatosplenomegaly, lytic bone lesions, lambda light chain monoclonal gammopathy, and infiltration of the bone marrow by dysplastic plasma cells, 10% of which demonstrated phagocytosis of erythroid cells. Electron microscopy demonstrated myeloma cells with prominent cytoplasmic microfilaments and erythroid cells in intracytoplasmic vacuoles. The myeloma cells did not phagocytose staphylococci in vitro. Phagocytic and nonphagocytic myeloma cells were tartrate-sensitive, acid-phosphatase positive, alpha-napthyl butyrate esterase negative, and did not form E rosettes or EAox(IgG) rosettes. The tumor cells were Tdt, Ia antigen, and SIg negative. Immunofluorescent staining for cytoplasmic light chains showed a monoclonal lambda pattern in nonphagocytic myeloma cells, and a probable monoclonal lambda pattern in phagocytic myeloma cells. These findings characterize the neoplasm as a monoclonal proliferation of differentiated plasma cells with the capability of erythrophagocytosis. Erythrophagocytosis by myeloma cells may have been responsible for the hemolytic anemia. The tritiated thymidine labeling index (LI%) was high (8%), suggesting a poor prognosis, despite a dramatic initial response to chemotherapy.
Adult↗
Effect of alcohols and selected solvents on serum osmolality measurements.
The method by which serum osmolality is measured can significantly affect the result if certain volatiles or solvents are present in the specimen. Commonly available solvents and alcohols were added to aliquots of pooled human serum to produce toxicologically relevant concentrations. Increasing concentrations of carbon tetrachloride, chloroform, mono-n-butyl ether (butyl cellosolve), 1, 1,1 trichloroethylene, toluene, and xylene did not change vapor pressure (VP) or freezing point depression (FPD) osmolality. Acetone, ethanol, isopropanol, and methanol in increasing concentrations produced a linear increase in FPD osmolality, but no change in VP osmolality. Only ethylene glycol produced a linear increase in VP and FPD osmolality across the range of concentrations studied. Despite the excellent correlation between osmolality and ethanol concentration in prepared serum samples, this relationship could not accurately predict patient ethanol concentrations from FPD osmolality. The osmolal gap, "delta" osmolality, (measured FPD minus calculated osmolality) did not correlate with the difference between measured FPD and VP osmolalities. Patient ethanol levels could not be predicted with accuracy using an equation based on the osmolal gap or "delta" osmolality.
Blood↗
Assay of cerebrospinal fluid protein: a rate biuret method evaluated.
We evaluated a rate colorimetric method (Beckman) for measuring total protein in cerebrospinal fluid. The automated instrument we used was Beckman's ASTRA TM. A 100-microL sample of spinal fluid is introduced into the biuret reagent in the reaction cell and the increase in absorbance at 545 nm is monitored for 20.5 s. Solid-state circuits determine the rate of alkaline biuret-protein chelate formation, which is directly proportional to the total protein concentration in the sample. The linear range of measurement is 120 to 7500 mg/L. Day-to-day precision (CV) over the range of 150 to 1200 mg/L ranged from 15.2 to 2.3%. The method was unaffected by radical alteration of the albumin/globulin ratio, but there is a positive interference in the presence of hemoglobin, a suppression in the presence of bilirubin, and no effect by xanthochromia. The method is precise, accurate, rapid, and convenient. The method was compared with the trichloroacetic acid method as performed on the Du Pont aca III, giving a correlation coefficient (r2) of 0.9693. The method is precise, accurate, rapid, and convenient.
Albumins↗
RBC zinc protoporphyrin to screen blood donors for iron deficiency anemia.
We evaluated a rapid RBC zinc protoporphyrin (ZP) test in 1,147 male and 615 female blood donors to study its value in screening for evolving iron deficiency anemia. Fifteen men (1.8%) and 32 women (7.9%) who returned to donate were found to be anemic. A matched sample analysis between anemic and nonanemic donors demonstrated significant differences in serum ferritin levels, percent iron saturation, and the RBC ZP level from samples collected during the initial evaluation. Red cell ZP correlated well with the natural logarithm of serum ferritin in both men and women who later became anemic. The predictive value of RBC ZP levels compared favorably with that of the serum ferritin level. We also observed a strong association between the yearly donation frequency and RBC ZP concentration. These findings indicate that predonation RBC ZP testing may be useful in screening for iron depletion and potential risk of anemia in blood donors.
Anemia, Hypochromic↗
Kinetics of the digoxin-aspirin combination.
Digoxin interacts kinetically with many drugs in man. These interactions may result in digoxin toxicity. Aspirin has been shown to raise serum digoxin levels in the dog. We evaluated the effect of aspirin on digoxin single-dose kinetics in eight healthy adults. Aspirin induced no change in digoxin total body clearance, volume of distribution, elimination half-life, or renal or creatinine clearance. Trough serum salicylate levels ranged from 93 to 163 microgram/ml. We conclude that no alteration is required in digoxin dosing when aspirin is used.
Adult↗
Serum CPK isoenzyme BB as an indicator of brain tissue damage following head injury.
In a study of 209 patients who had serum drawn for assay of creatine phosphokinase (CPK) isoenzymes, an attempt was made to correlate elevation of CPK brain fraction (BB) with occurrence of brain injury and to evaluate its sensitivity as an indicator of the presence of brain damage. Thirty-three patients had suffered serious head trauma. However, of the ten patients in coma, only three had elevated serum CPK-BB levels. Twenty-four of the other 176 patients who had no history and head injury also had positive BB fractions. Serum CPK-BB level was therefore an unreliable indicator of the extent of brain damage.
Adolescent↗
Cimetidine decreases theophylline clearance.
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Aged↗
A cellulose acetate electrophoretic procedure evaluated for quantitation of high-density lipoprotein cholesterol.
We evaluated the performance of a commercially available cellulose acetate electrophoretic method for quantitating high-density lipoprotein cholesterol (I) in serum by comparing it to a method involving precipitation with dextran sulfate-500/Mg2+. In both methods, enzymic reagents are used for cholesterol measurement. For electrophoretic measurement of I the mean intramembrane CV ws 4.1% (at 220 to 360 mg/L) and the intermembrane CV ranged from 12.2 to 21.0% (at 220 to 880 mg/L). Interassay precision was significantly better for the precipitation method (CV = 3.9% at 390 mg/L). The electrophoretic procedure demonstrated significant measurement bias, both at high and low I concentrations. However, low-density lipoprotein cholesterol, measured electrophoretically correlated well with its calculated concentrations obtained by the precipitation method. Measurement of I by this electrophoretic procedure did not achieve the accuracy and reproducibility that have been demonstrated for precipitation methods and that are necessary for reliable clinical interpretation of results for I.
Blood Chemical Analysis↗
Measurement of near-normal concentrations of erythrocyte protoporphyrin with the hematofluorometer: influence of plasma on "front-surface illumination" assay.
Zinc protoporphyrin in erythrocytes increases in iron depletion. Because the hematofluorometer directly measures zinc protoporphyrin in whole blood, it may therefore be a useful screening instrument for detecting iron deficiency. We evaluated its performance with normal to slightly above-normal zinc protoporphyrin concentrations (0.2 to 2.0 mg/L) in erythrocytes, because this is a critical range for differentiating normal and iron-deficient individuals. There was excellent correlation (r2 = 0.900) between erythrocyte protoporphyrin as measured by an extraction procedure and as measured directly with the hematofluorometer. However, at these concentrations, plasma caused hematofluorometer readings to be spuriously high, by 2.4 to 89.4%, an effect due to the instrument's optical design. The effect can be eliminated by washing the cells free of plasma or by allowing erythrocytes to displace plasma by settling to the illuminated surface before the measurement. The interference does not affect the hematofluorometer's sensitivity, but abnormal results obtained for whole blood should be confirmed with more-specific tests, and interlaboratory precision may be influenced if whole-blood samples are used. A 1-min delay from sample placement to measurement decreased zinc protoporphyrin values by 2.6 to 36.9%. We also describe the use of cryopreserved control erythrocytes, for which the CV is 2.3% for a concentration of 0.96 mg per liter of erythrocytes, which are not affected by time of measurement, and which are stable for three months.
Blood Chemical Analysis↗
Rate-nephelometric inhibition immunoassay of phenytoin and phenobarbital.
A proposed rate-nephelometric inhibition immunoassay of phenytoin and phenobarbital in human serum involves the sequential addition to buffer of 42-microL aliquots of sample containing the hapten (drug) of interest, a hapten conjugate (drug-equine apoferritin), and specific antibody to the hapten. The drug and the drug conjugate compete for the binding sites on the antibody. The free hapten-antibody complex is soluble and so does not scatter light, whereas the complex of antibody and drug conjugate is insoluble and thus scatters light. The latter immunoprecipitation is competitively inhibited by free hapten. Thus the higher the concentration of free hapten present, the fewer immunoprecipitin complexes are formed, and the less light scatter. Precision, accuracy, linearity, analytical recovery, and comparison with patients' samples assayed with the DuPont aca were excellent. There was no significant interference from hemolysis, icterus, or lipemia. Many potentially interfering drugs and metabolites were checked for cross reactivity, with negative results. Reaction times range from 30 to 50 s.
Antibodies↗
Adaptation of the enzyme-multiplied immunoassay for methotrexate to the centrifugal analyzer.
We adapted the homogeneous enzyme-multiplied immunoassay for methotrexate to the centrifugal analyzer. The sensitivity of the assay has been extended from 200 nmol/L down to 12.5 nmol/L. Several protocols may be followed, depending on whether the samples to be tested are from patients on low- or high-dose methotrexate regimens. Precision, accuracy, and sensitivity were satisfactory. Comparison with the enzymic-inhibition method (x) gave the following least-squares regression: y = 1.002 x - 0.013 mumol/L; r2 = 0.9721; Sy/x = 0.014 mumol/L.
Centrifugation↗
Evaluation of a new homogeneous enzyme inhibitor immunoassay of serum thyroxine with use of a bichromatic analyzer.
We evaluated a new homogeneous enzyme immunoassay of thyroxine with use of a discrete analyzer (the ABA-100 Bichromatic Analyzer), modified with an auxiliary dispenser assembly. The assay is based on inhibition of hydrolysis of the substrate, acetyl-beta-(methylthio)choline iodide, by acetylcholinesterase (acetylcholine hydrolase; EC 3.1.1.7). Thyroxine covalently linked to a cholinesterase inhibitor irreversibly inhibits acetylcholinesterase, but if this thyroxine conjugate is bound to antibody it is not inhibitory. Seventy-five patients' samples may be analyzed in 1 h of instrument time. Precision and accuracy are excellent, results correlate well with those by radioimmunoassay, and there were no instances of confused clinical interpretation resulting from use of the proposed assay.
Autoanalysis↗
Changes in immunoglobulin control sera.
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Drug Stability↗
Immunochemical determination of human immunoglobulins: use of kinetic turbidimetry and a 36-place centrifugal analyzer.
We describe the measurement of human immunoglobulins IgG, IgA, and IgM in diluted sera, with diluted commercial monospecific antisera, with use of a 36-place centrifugal analyzer (RotoChem IIa; American Instrument Co., Silver Spring, MD 20920). The assay involves a two-point kinetic turbidimetric technique. The changes in absorbance at 340 nm between 10 and 255 s are taken for standard curve construction with use of a computer-generated cubic least-squares fit. Patients' samples are quickly calculated from the stored curve. Multiple time-interval readings are taken to observe the reaction kinetics. The lowest detectable concentrations are: IgG, 5 mg/L; IgA, 20 mg/L; and IgM, 20 mg/L. Correlation with radial immunodiffusion was excellent. Precision, accuracy, linearity, and sensitivity were very acceptable. Antigen or antibody excess can be easily detected. The accuracy of the proposed method when measuring idiotypic monoclonal proteins is greater than radial immunodiffusion. Up to 30 patients' samples can be analyzed at one time, and calculation of test results by use of the computer program is efficient and rapid.
Autoanalysis↗
Rate nephelometric measurement of rheumatoid factor in serum.
We describe the measurement of rheumatoid factor in human sera with a rate nephelometer. The National Reference Preparation for Rheumatoid Factors is used to calibrate the assay in International Units. We used Hyland Positive Control, Level I, as a secondary standard. The standard curve is exponential, but is linear when plotted on log-log graph paper. Aggregated immune globulin (IgG) is the antigen used to detect rheumatoid factor (IgM-class antibody to IgG). The rate reaction measures the rate of increase in light-scatter by the antigen-antibody complexes; the reaction takes place in 17 to 20 s. Precision, linearity, and accuracy are excellent. Results agree well with those for a commonly used latex precipitation test. The advantages of speed, quantification in International Units, and superior discrimination of concentration as compared to serological titration provide a more reliable test for use in the diagnosis and treatment of rheumatoid arthritis.
Antigen-Antibody Complex↗