Abraham Rimon

The plasmin inhibitors of human plasma: III. Purification and partial characterization

Abstract Purification of plasmin inhibitors of human plasma by ion-exchange chromatography on DEAE-Sephadex and by electrophoresis on starch-gel is described. The purified material was found to be an α1-globulin, heat and acid labile and containing 8% carbohydrates. A mol. wt. of 55 000 was calculated from a sedimentation constant of 3.3 and a diffusion constant of 5.2. The purified inhibitor exhibited both “slow” and “immediate” antiplasmin activities.

Purification properties and specificity of cathepsin D from Cyprinus carpio.

Cathepsin D was purified 750-fold from a homogenate of Cyprinus carpio muscles. The purified enzyme has a molecular weight of 36,000, is inhibited by pepstatin and is active between pH 2.7 and 3.7 when tested on hemoglobin as the substrate. It consists of two isoenzymes with pIs of 5.65 and 6.1, respectively. The mode of cleavage of the beta chain of oxidized insulin was determined by analysis of the N-terminal amino acids of the cleaved peptides. The major points of cleavage of the beta chain of oxidized insulin are 56% at Tyr16-Leu17 and 40% at Phe25-Tyr26. The minor points of cleavage are at Leu15-Tyr16, Phe24-Phe25, Gly23-Phe24, Leu11-Val12, Ala14-Leu15 and Gln4-His5.

Simple Rapid Osmotic Fragility Test Proposed as a Routine in Blood Banks

A rapid micromethod for recording red cell osmotic fragility by continuous decrease of salt concentration was used. It requires one drop of blood and it yields an automatically recorded curve and/or its derivative in less than ten minutes. The blood of 100 donors was tested on the day after donation. One case out of 100 showed an abnormal fragility curve. The deterioration of the blood during storage in ACD at 4 C. and the consequent modification of the fragility curve was followed. Marked individual variations were found in the rate of deterioration during storage. While some of the blood samples show a sizable os‐motically more fragile population after three weeks of storage, others remain within the range of normal osmotic fragility. The correlation between the estimated osmotically resistant population after storage and the per cent survival 24 hours after transfusion, as evidenced by transfusing Cr51 tagged erythrocytes, indicate that transfusion of some of the donated blood at the third week of storage may be relatively ineffective because of poor survival. The good conservation of some of the blood samples even after three weeks suggests that the routine discarding of blood after three weeks of storage is wasteful.

Studies on the activation of plasminogen I. Preparation and properties of an insoluble derivative of streptokinase

1. n1. An insoluble derivative of streptokinase was prepared by coupling streptokinase to a diazotized copolymer of p-aminophenylalanine and leucine. n n2. n2. The product was shown to be functionally identical to soluble streptokinase. n n3. n3. Some proteins, especially casein, were found to accelerate activation of plasminogen with bound streptokinase; other proteins, e.g. albumins, had no influence on the reaction, whereas tosyl-l-argininemethyl ester inhibited it. n n4. n4. Using bound streptokinase, it was possible to separate the activation phase from the caseinolytic phase in the plasmin system.

Biochemical and Electron Microscopic Study of Preserved Erythrocytes

The age population distribution as judged by the ultrastructure of red cell membranes (“ghosts”), prepared by gradual osmotic hemolysis, was studied during storage in parallel with some of the biochemical changes that characterize the storage lesion. The loss of cholesterol and phospholipids and the decrease in DPG and the delayed decrease of ATP together with the increase in inorganic phosphate indicated a typical storage lesion, however, no significant modification in the proportion of structurally old red cell membranes was found. It is concluded that the storage lesion can not be morphologically identified with physiological aging of erythrocytes from the electron microscopical point of view.

The chemical and immunochemical identity of amyloid.

Amyloidosis, first described by Rokitansky (1842), is characterized by the deposition in the heart, tongue, liver, spleen, kidneys, adrenals and, to a smaller extent, in other tissue, of a whitish interstitial substance that resembles starch both by its physical appearance and by its response to staining with iodine solution. It was these properties of the substance which prompted Virchow (1853 and 1854) some 120 years ago, to suggest the name “amylid” for it, although soon after amyloid was found to be essentially a protein (Friedreich and Kekule, 1859; Kuhne and Rudneff, 1865).