Theodor H. Weber

Characterization of lymphocyte-stimulating blood cell-agglutinating glycoproteins from red kidney beans (Phaseolus vulgaris)

Abstract 1. 1. Commercially available phytohaemagglutinin from red kidney beans (Difco, Phytohemagglutinin P) contains glycoproteins with lymphocyte-stimulating and red and white blood cell-agglutinating activity. By a sequence of steps involving SE-Sephadex C-50, QAE-Sephadex A-50 and Sephadex G-200 chromatography, two different lymphocyte-stimulating agglutinins were isolated in homogeneous form. One was purely leucoagglutinating, while the other was erythroagglutinating and also showed leuco- and mixed agglutinating activity. 2. 2. The physicochemical properties of the agglutinins were studied by analytical ultracentrifugation, isoelectric focusing and polyacrylamide disc electrophoresis. The leucoagglutinin was shown to have the following properties: Mr = 140 000, s020,w = 6.8 S, pI = 5.0; the erythroagglutinin respectively: Mr = 150 000, s020,w = 7.1 S, pI = 6.5. The partial specific volume of both agglutinins was 0.75 ml/g. 3. 3. The molecular subunit structure of the agglutinins was studied by analytical ultracentrifugation in 5.8 M guanidine hydrochloride, by polyacrylamide electrophoresis in buffers containing sodium dodecyl sulphate and by isoelectric focusing in 8 M urea. Both agglutinins were found to be composed of 4 subunits of similar size held together by noncovalent bonds. Isoelectric focusing of the subunits revealed that the leucoagglutinin contained subunits of only one type, while the erythroagglutinin contained subunits of several types, one type being identical to the subunits of the leucoagglutinin, the other being specific for the erythroagglutinin. A molecular weight of 36 000 was calculated for the subunits. 4. 4. The lymphocyte-stimulating activity of both agglutinins could be abolished by oxidation with NalO4, which treatment only slightly affected the agglutinating capacities.

The vitamin B12-binding protein in human leukocytes

Abstract 1. 1. Human leukocytes bind vitamin B12 added in vitro at a rate of 8.9 mμg/107 cells. Purified peripheral lymphocytes bind about nine times less per cell. 2. 2. A method is described for the purification of the leukocytic vitamin B12-binding trace protein. 3. 3. Immunoelectrophoresis of the purified trace protein labelled with 57Co-labelled vitamin B12 gives a radioactive precipitate with anti-luekocyte, anti-gastric juice and anti-saliva sera. 4. 4. The molecular weight of the binding protein has been estimated by gel filtration as about 115 000–117 000. 5. 5. The vitamin B12-binding protein appears to be synthesized in the leukocytes, for incorporation of [14C]leucine into this protein can be demonstrated on vitro. This observation adds further support to the hypothesis that the granulocytes aer one source of vitamin B12-binding proteins (devoid of intrinsic factor activity) found in serum and in the digestive fluids.

TRANSIENT ERYTHROBLASTOPENIA IN CHILDHOOD A Study of 15 Cases

ABSTRACT. A survey is presented of 15 patients from the Aurora Hospital and 35 patients reported in the literature with transient erythroblastopenia of childhood (TEC). The children were hospitalized because of pallor and tiredness, some of them having signs of mild infection. They displayed normochromic anaemia, reticulocytopenia and erythroblastopenia during the severe stage of the disease. In addition, they had moderately high values for serum iron and iron‐binding saturation. No other haematological, chemical or cytogenetic abnormalities could be demonstrated. 80% of the children were between 6 and 48 months old and the sexes were equally affected. In the 15 patients from the Aurora Hospital a barely significant (p=0.02‐0.05) association with blood group A was recorded. Remission, indicated by a rise in the reticulocyte count, begins within a week after the diagnosis is made, even without treatment. The aetiology of the disease is unknown. Analysis of the red blood cell population at the time of diagnosis indicates that damage to the red cell precursors has occurred 2–3 months before the child is brought for examination.

A method for the quantitative evaluation of radioisotope renograms

Abstract A mathematical model for renography is presented. The model is based solely upon physiological quantities. With the aid of this model the following information can be deduced: 1. (1) The individual clearance of the kidneys expressed in percent of total clearance. 2. (2) An estimate of the ratio of the urinary flow to the volume of the renal pelvis. This quantity is obtained by comparing the measured renogram with simulated renograms, in which the urinary flow and the volume of the renal pelvis are known. 3. (3) In additon the measurement procedure gives the ordinary renogram and a blood clearance curve. The solutions of the differential-difference equations involved, are presented. Oscillations (waves or steps) in the excretory phase, often observed in measured renograms, were predicted by the mathematical treatment and must be regarded as normal phenomena.