Identification of particulates in vaccine formulations containing aluminum phosphate.

Density gradient centrifugation was used for identification of particulates in vaccines formulated with aluminum phosphate (AlPO(4)) adjuvant. Protein-derived particulates are sporadically seen in protein pre-filled formulations where siliconized syringes are employed. These particulates are difficult to distinguish from the AlPO(4) suspension.

Effects of ligand heterogeneity in the characterization of affinity columns by frontal analysis.

This study examined how the binding capacities and equilibrium constants measured by frontal analysis are affected by ligand heterogeneity in affinity columns. Equations derived for n- and two-site systems gave good agreement with results obtained for the binding of L-thyroxine to a column containing human serum albumin (HSA) and for the binding of (R)-warfarin to coupled columns containing HSA or pigeon serum albumin. The same equations were used to examine how different degrees of ligand heterogeneity affected the apparent binding capacities or equilibrium constants measured using the linear range of double-reciprocal frontal analysis plots.

Pneumatic transport exacerbates interference of room air contamination in blood gas samples.

Objective: To characterize and control the potential interference to P(O2) determinations when blood contaminated with air is sent via a pneumatic tube system (PTS).

Design: Both tonometered blood at P(O2)s of 65, 75, 142, and 339 mm Hg and arterial blood gas samples from patients with baseline P(O2)s from 70 to 400 mm Hg were analyzed for P(O2) to determine possible effects of air contamination from PTS transport.

Setting: A large teaching hospital in which a variety of personnel routinely send samples to the laboratory by PTS transport.

Ultrafiltration discrepancies in recovery of myoglobin from urine.

We investigated the efficiency, accuracy, and reliability of the ultrafiltration/dipstick methodology commonly used to diagnose myoglobinuria. Twenty-five myoglobin-containing urine specimens were filtered by centrifugation for 15 min at 1500g through a Centricon-30 membrane filter. Both the original specimen and filtrate were assayed for myoglobin.