Physical, chemical, and ultrastructural studies of water-soluble human amyloid fibrils. Comparative analyses of nine amyloid preparations

Amyloid fibrils were isolated from the tissues of nine patients with amyloidosis in a state of high purity by homogenization of the tissue followed by extraction with distilled water. Physical, chemical, and ultrastructural studies suggest that amyloid fibrils from different individuals resemble each other, but are not identical. In tissue sections as well as by negative staining of isolated fibrils, morphologic variations were observed. Among the isolated fibrils at least three types were noted. The majority resembled those described previously. However, one subject had two types of fibrils which differed in size and appearance. Most of the preparations sedimented as a single component with a sedimentation coefficient of 45-50S or as a larger polymer. However, two of the preparations had sedimentation coefficients of 8-9S, and a third one had a major 95S component and a minor 9S fraction. While the preparations of amyloid were not sufficiently pure for amino acid analyses, peptide maps demonstrated differences among amyloid preparations from different subjects. The amyloid fibrils in their native state proved to be remarkably resistant to digestion by a number of proteolytic enzymes. Several chemical methods were tried to produce smaller subunits. Of these, the most successful one was the use of 0.1 M NaOH which yielded a smaller, soluble fraction with sedimentation coefficients ranging from 1.1 to 2.8S. Accompanying this degradation, there was little loss of peptides or carbohydrates. Based on the results of the chemical analyses, it is estimated that the subunit produced by sodium hydroxide had a molecular weight of approximately 35,000-40,000.

Relationship between the uptake, binding and pharmacological action of procaine in the isolated heart

1. The uptake, efflux and pharmacological actions of procaine hydrochloride were studied on isolated hearts of female guinea-pigs. The hearts were perfused with Krebs solution containing (14)C-procaine (0.1-500 mug/ml.) by the Langendorff technique at 37 degrees C, using a constant flow pump. Hearts and cardiac effluent were assayed for procaine by liquid scintillation spectrometry.2. Accumulation of procaine did not appear to involve active transport mechanisms for the following reasons. The rate of procaine uptake was most rapid at the highest perfusion concentration (500 mug/ml.), when it was three times faster than at the lowest concentration (0.1 mug/ml.); it was not affected by lowering the temperature to 3 degrees C. The ratio of the concentration of procaine in the heart to the concentration in the perfusing fluid decreased with increasing concentration in the perfusion fluid.3. When the efflux of (14)C-procaine from hearts previously perfused with procaine-containing Krebs solution for 10 min was compared with the efflux of (14)C-inulin, the patterns of efflux of both compounds were similar, and showed at least two exponential components. At the highest concentration of procaine (500 mug/ml.) the efflux of procaine was more rapid than that of inulin.4. A relationship was found between the pharmacological action of procaine, the rate of uptake and the level of procaine in the heart. When the procaine-containing perfusion fluid was changed to a procaine-free solution, the heart rate increased rapidly, and there was a rapid decline in the levels of procaine in the hearts.5. It is concluded that guinea-pig hearts accumulate procaine by a passive diffusion process, and that the pattern and rate of efflux indicate that the drug is loosely bound. If it is permissible to extrapolate from these findings to the antiarrhythmic effect in man, the short duration of its action may be due to loose binding rather than to rapid metabolic inactivation.

A two-dimensional thin-layer chromatographic procedure for the estimation of plasmalogens

1. The use of two-dimensional thin-layer chromatography is described that allows the rapid and simultaneous determination of phospholipid classes and their constituent plasmalogens. 2. The method is based on the specific hydrolysis of plasmalogens to (2-acyl) lysophospholipid in the presence of a mercuric chloride spray reagent. 3. The proportion of mercuric chloride-labile phospholipid present in each phospholipid class, calculated on the basis of phosphorus recoveries from the charred chromatogram, was compared with the proportion of long-chain aldehyde and of total lipid phosphorus found in small-scale preparations of each class of phospholipid. 4. The method permits the determination of individual plasmalogens on preparations containing as little as 0.2mug.atom of total lipid phosphorus.