Comparison of three different activation methods for coupling antibodies to magnetisable cellulose particles.

The periodate and 1,1'-carbonyldiimidazole activation methods were compared with the cyanogen bromide procedure for coupling antibodies to magnetisable cellulose/iron oxide solid-phase particles. Fluoroimmunoassays for quinine, primaquine, normetanephrine and cannabinoids were employed to assess the binding properties of such coupled solid phases. The cyanogen bromide and 1,1'-carbonyldiimidazole methods gave similar products in most cases, while the specific binding capacity of periodate coupled particles was between two and five times lower. Nevertheless, comparable standard curves could be obtained with solid phase coupled by each method. The periodate and 1,1'-carbonyldiimidazole methods are acceptable alternatives, notably for laboratories lacking the facility to handle the toxic cyanogen bromide.

Solid-phase fluoroimmunoassay of human albumin in biological fluids.

A simple fluoroimmunoassay for the determination of albumin levels in serum, urine and cerebrospinal fluid is described. It employs magnetisable particles to which antibodies to human serum albumin are covalently linked, and albumin labelled with fluorescein. Equilibrium is reached within 30 min, when separation of the bound and free fractions of the labelled albumin is performed by precipitation of the particles either with a magnet or by centrifugation. Measurement of the fluorescence in the supernatant (the free fraction) reflects the albumin concentration of the standards or samples. Correlation studies with an automated immunoprecipitation technique show good agreement.

Salivary cortisol determination: adaptation of a commercial serum cortisol kit.

The determination of cortisol levels in saliva offers a number of significant advantages as compared with plasma or serum measurements, and radioimmunoassay is the technique of choice because of the greater sensitivity required. To date, the assay of salivary cortisol has been limited to only a few centres employing 'in-house' reagents. We describe some simple modifications of a commercial kit, designed for the assay of cortisol in serum and urine, which allow direct and rapid determination of the steroid in saliva. These modifications enable any laboratory with access to a gamma counter to perform large numbers of salivary cortisol assays at relatively low cost.

Organization of native and in vitro-reassembled myosin filaments from lobster tonic muscle.

Tonic muscle of the crusher claw of the American lobster (Homarus americanus) was investigated with respect to sarcomeric organization and the capacity for self-assembly of extracted myosin for comparison with the same properties of rabbit muscle. Native myosin filaments in the lobster muscle are much longer than in rabbit skeletal fibers, and differ further in sarcomeric organization in showing an actin-to-myosin relationship in which two actin filaments are shared between adjacent myosins in a 12-membered orbital. The self-assembly of lobster myosin into filaments comparable in length and the fine structure to the natural filament was achieved in the presence of excess Mg2+, a condition not required for rabbit myosin self-assembly. Results of in situ and self-assembly studies indicate a difference in molecular organization between lobster and rabbit myosin filaments and of the inferred presence of regulatory factors in the formation of these ultrastructural elements. These studies represent the groundwork for an investigation of in vitro polymerization of actin in association with the synthetic lobster myosin filament.

Zinc gluconate and the common cold: a controlled clinical study.

A report in 1984 on the success of zinc gluconate against common cold symptoms could not be confirmed in three subsequent studies, which are now known to have used formulations that inactivated zinc. A non-chelating formulation including glycine, which releases 93% of contained zinc into saliva, was tested in a randomized, placebo-controlled, double-blind trial in 73 young adults. Efficacy was recorded in symptom diaries using a symptom severity rating. Patients' symptoms first appeared 1.34 days prior to entry to the study in both groups. Disappearance of symptoms occurred after an additional 4.9 days for zinc-treated patients versus 6.1 days for placebo-treated patients. A difference was noted in the efficacy of treatment if it was started 1 day after symptom onset: cold duration was an additional 4.3 days in zinc-treated patients compared with 9.2 days for placebo-treated patients. Cough, nasal drainage and congestion were the symptoms most affected, and only mild side-effects were noted.

A randomized controlled trial of oral albuterol in acute cough.

BACKGROUND: Beta-agonist agents have been used for bronchospasm and cough in a variety of settings. We sought to evaluate the efficacy of oral albuterol for acute cough in ambulatory adults. METHODS: We performed a prospective, randomized, controlled, double-blind clinical trial comparing albuterol 4 mg by mouth three times daily for 7 days with placebo in 104 adults. Subjects had cough of less than 4 weeks' duration and no evidence of pneumonia, asthma, or chronic obstructive pulmonary disease. All subjects were enrolled at the walk-in clinic of a rural academic medical center. RESULTS: There was no significant difference between treated and control subjects in any measure of efficacy including cough severity score, reduction in sleepless nights, utilization of health care, or return to full activity. There were significantly more reports of "shakiness" and "nervousness" among albuterol-treated subjects than among controls. CONCLUSIONS: Oral albuterol should not be used in unselected patients with acute, nonspecific cough.

Radioimmunoassay of salivary digoxin by simple adaptation of a kit method for serum digoxin: saliva/serum ratio and correlation.

A robust commercial radioimmunoassay kit for serum digoxin was adapted to salivary assay by simple procedural modifications and shown to have satisfactory sensitivity, precision, accuracy, and specificity. The digoxin saliva/serum concentration ratio in 50 hospital patients was 0.67 +/- 0.10 (mean +/- SD), and the levels were well correlated (r = 0.96). Similar saliva/serum ratios were found in two normal subjects who took digoxin orally, and the free fraction in serum, determined by equilibrium dialysis, was found to equate with the salivary drug level. Digoxin appeared in saliva at its maximum level within 1 min of intravenous injection. Although previous studies of salivary digoxin have given widely discrepant results, the present findings are entirely consistent with the simple expectation that digoxin should appear in saliva by passive diffusion. Salivary sampling is suitable for the monitoring of digoxin therapy and pharmacokinetics, and the modified radioimmunoassay should be of value to laboratories wishing to introduce this technique.

Polarisation fluoroimmunoassay of serum and salivary cortisol.

Polarisation fluoroimmunoassays for serum and salivary cortisol were developed using the steroid labelled at the 3-position with fluorescein and antiserum raised in sheep. To avoid interfering factors present in the biological fluids, cortisol was extracted with dichloromethane prior to assay, which was then accomplished without the need for any further separation or blank-correction procedures. The methods were sufficiently sensitive to cover the normal morning ranges for serum and salivary cortisol and correlated acceptably with established fluorimetric and radioimmunoassay techniques. The salivary cortisol assay was more precise than the serum assay, reflecting the greater case with which cortisol may be extracted from saliva. The potential usefulness of salivary cortisol assays was illustrated by a preliminary study showing that the circadian variation in three children was similar to that in an adult.

Anti-Jka, -C, and -E in a single patient, initially demonstrable only by the manual hexadimethrine bromide (Polybrene) test, with incompatibilities confirmed by 51Cr-labeled red cell studies.

Published reports have confirmed the superior sensitivity of the manual hexadimethrine bromide (Polybrene) test (MPT) for demonstrating many alloantibodies in vitro; however, the clinical significance of alloantibodies demonstrable exclusively by MPT has not been shown conclusively. A patient with macroglobulinemia experienced chills, fever, hemoglobinemia, and hemoglobinuria following the transfusion of 1 unit of red cells (RBCs) shown to be compatible by the low-ionic-strength antiglobulin (LIS-AG) method. Serologic investigation was negative. Intravascular hemolysis occurred with a second "compatible" unit. Serologic studies were again negative by LIS-AG and ficin-AG methods, but revealed anti-Jka by MPT. Both donors were Jk(a+b-), and 51Cr studies of the second donor's RBCs revealed a t1/2 of less than 30 minutes, with marked intravascular hemolysis. A LIS-AG-compatible Jk(a-) unit was transfused uneventfully, but with no rise in hematocrit. MPT next revealed anti-C; subsequent 51Cr studies with the Jk(a-), Cc donor's RBCs showed a 51Cr t1/2 of 100 minutes with slight intravascular lysis. Four transfusions of Jk(a-), C- blood were uneventful, but 5 days later the patient's hemoglobin declined. The following day, anti-E was demonstrable exclusively by MPT. 51Cr-labeled Jk(a-), C-, E- RBCs had normal 24-hour survival. The patient's hemoglobin rose to 11 g per dl following transfusions of Jk(a-), C-, E- RBCs, and he was discharged. In vitro studies employing the patient's purified IgM paraprotein revealed no interference with alloantibody binding or detection.

Polarization fluoroimmunoassay of 11-deoxycortisol in serum and saliva.

We developed polarization fluoroimmunoassays for 11-deoxycortisol in serum and saliva. To avoid interfering factors, the steroid was initially extracted from the biological fluids with dichloromethane. Assays could then be completed without any further separation procedures or need to correct for blank signals. The serum assay was suitable for following the response to the metyrapone test and results correlated acceptably with those by an established, specific, direct 125I-radioimmunoassay. The method is not sufficiently sensitive to detect 11-deoxycortisol in normal saliva, but greatly increased concentrations were found in post-metyrapone saliva and results agreed well with those by the radioimmunoassay as modified for salivary assay. Salivary 11-deoxycortisol assay would provide a convenient means of monitoring results of the metyrapone test.