Granulopoiesis in severe congenital neutropenia

The pathogenesis of the granulopoietic failure in three children with severe congenital neutropenia was studied. Mature neutrophils were absent from both peripheral blood and bone marrow. Assay of bone marrow granulocyte colony-forming cells (CFU-C) in a methylcellulose tissue culture system using colony-stimulating activity (CSA) from peripheral blood leukocytes demonstrated normal or increased concentrations of CFU-C compared to those from marrows of 60 age-matched controls. Colonies were of normal size and by light microscopy appeared to contain granulocytes in all stages of maturation including the mature polymorphonuclear neutrophil. CFU-C from peripheral blood of two patients were normal. Production and activity of CSA from the patients' peripheral blood leukocytes and urinary CSA excretion were normal. No serum inhibitors against CFU-C or CSA could be demonstrated using both control and autologous marrow. The defect did not appear to be due to a lack of granulocytic stem cells, a reduction of humoral stimulators of granulopoiesis, nor the presence of an inhibitor as measured by these techniques.

Erythroid colony growth in congenital hypoplastic anemia

Four children with congenital hypoplastic anemia (Diamond-Blackfan syndrome) and 30 control children with normal erythropoiesis were studied by a cell culture method in which human marrow, grown in a plasma clot, responds to added erythropoietin (EPO) with the appearance of discrete colonies of nucleated erythroid cells. The colonies arise from EPO-responsive stem cells and are not related to the number of morphologically identifiable marrow erythroids plated. Results of studies on control marrow indicated that without EPO there was little or no colony formation. Increasing EPO doses or nucleated marrow cells per culture resulted in a linear increase in colony numbers. The optimal EPO concentration of 2.5 U/ml yielded a mean of 158 +/- 79 colonies/1 x 10(5) nucleated cells on day 7 of incubation. Even in the absence of recognizable erythroids, marrows of all four patients with anemia grew erythroid colonies. Two patients on no therapy had decreased colony numbers. The other two, on prednisone, had normal numbers. Sera from patients did not inhibit colony formation from either autologous or control marrow. In contrast, serum from an adult with acquired pure red cell aplasia produced striking inhibition of colony growth. It appears that the red cell failure in this disorder is not due to an absence of erythroid stem cells, and a serum inhibitor to erythropoiesis as seen in the acquired disease is unlikely.

Post recognition ion dependent events in mitogen induced lymphocyte proliferation and in cytotoxic effector cell responses

This review discusses the increased permeability and enhanced uptake transport of monovalent and divalent cations following mitogen-induced lymphocyte proliferation. The observed Ca2+ uptake is discussed in terms of gated Ca2+ channels. The importance of divalent cations, particularly Ca2+, is discussed in terms of triggering of cytotoxic effector cell responses for three model systems (antibody dependent cytotoxicity, mitogen-induced cytotoxicity and cell mediated cytotoxicity); (85).

Hemoglobin-oxygen affinity in hypophosphatemic rickets

In 14 patients with simple X-linked hypophosphatemic rickets, 5 were below the third percentile in height and 9 were between the third and twenty-fifth percentile. Although the mean serum inorganic phosphorus level was only 2.01 +/- 0.65 (normal range for all age groups is 3.8 to 6.0 mg/100 ml), both the mean values for red cell 2,3-diphosphoglycerate (2,3-DPG) and adenosine triphosphate (ATP) were normal at 4.78 +/- 1.23 and 1.02 +/- 0.17 mumol/ml of red blood cells respectively. Moreover, the mean P50 value was normal at 26.4 +/- 0.9 mmHg. These normal oxygen transport data make unlikely any proposal that short stature seen in these patients is secondary to chronic tissue hypoxia. They also indicate that the intra-erythrocytic organic phosphate levels are maintained at normal levels despite profound chronic hypophosphatemia.

Effect of altitude exposure on platelets

Since decompression from depth is known to produce a fall in platelet count, the effect of altitude decompression and high-altitude exposure on platelets was investigated. Sixteen subjects decompressed without hypoxia to 20,000 ft simulated altitude for two hours showed a significant (P less than 0.01) drop in circulating platelet count of approximately 10% for three days following decompression. Four of five subjects similarly exposed had a shortened autologous platelet survival compared to that prior to exposure. Subjects exposed to 9,800 ft and then 17,600 ft in a mountain environment showed a significant mean decrease in platelet count on day 2 of 7% and 25% respectively, which had returned to control by day 5. Nonhypoxic and hypoxic decompressed rabbits which received homologous chromium-51-labeled platelets had an increase in lung radioactivity compared with sea-level controls. It is postulated that altitude decompression produces platelet reductions similar to these seen after decompression from depth, and that platelets sequester in the pulmonary vascular bed.

Induction of increased calcium uptake in mouse T lymphocytes by concanavalin A and its modulation by cyclic nucleotides

The binding of concanavqlin A to T but not B mouse spleen lymphocytes increases Ca-2+ uptake in these cells which is measurable by 45 s and complete by 1 min. Dibutyrl cyclic AMP, but not sodium azide inhibits induced Ca-2+ uptake, wheras dibutyryl cyclic GMP enhances it. B cell mitogens do not cause a similar Ca-2+ uptake in mouse B lymphocytes. The induction of increased Ca-2+ uptake by T cells is discussed in terms of gated membrane channels for Ca-2+.

A human IgG myeloma protein crystallizing with rhombohedral symmetry

The M-component in the serum of a patient with multiple myeloma and hyperviscosity syndrome was found to be an immunoglobulin of the IgG-1(K) class which crystallized spontaneously from the serum. After purification, the protein crystallized readily under a variety of conditions. X-ray diffraction studies indicated a rhombohedral lattice with cell dimensions: aR = 170 ± 5 Å, αE = 109 ± 2°. Assuming a molecular weight of 1.5 × 105, the crystals have been calculated to contain 66 ± 3% solvent, and six molecules per unit cell.Screening of the protein for antibody-like activity against a wide range of antigens gave positive results in several instances, in particular when tested against gum Karaya. This reaction was inhibited by D-glucuronic acid.

An Investigation into the Nature of π-Inductive Effects: π Polarization Effects in Phenylalkanes with Polar or Charged Substituents

pH dependent 13C chemical shifts for phenylglycine, phenylalanine, and phenylalanyl derivatives demonstrate that the electronic distribution of the phenyl group depends upon the distance of charged groups from the phenyl ring. The pattern of chemical shifts and the results of CNDO/2 MO calculations indicate that this is due to polarization of the phenyl π electron system. 13C chemical shifts and CNDO/2 calculations for α- and β-substituted phenylalkanes (substituent = NH3+, Cl or Br) provide further evidence for a π polarization effect.

Carbon-13 chemical shifts accompanying helix formation

The helix–coil transition in an aqueous solution of poly-L-glutamic acid has been observed using 13C nuclear magnetic resonance. The transition from coil to helix results in pronounced deshielding of the carbonyl and C-α carbons of the polymer and a less dramatic shielding effect on the C-β carbon. These results are contrasted with the titration behavior of L-glutamic acid to delineate those shifts directly attributed to the secondary-structure change. The biological significance of this observation is supported by the 13C chemical shift differences observed for the 13C-enriched phenylalanyl residue 8 in the free 1–15 amino-terminal peptide of ribonuclease (RNase) and the 1–15 peptide:RNase S-protein complex.

Seizure disorders and anemia associated with chronic borax intoxication

During the course of investigation of two infants with seizure disorders it was discovered that both had been given large amounts of a preparation of borax and honey which resulted in chronic borate intoxication. In one child a profound anemia developed as well. The symptoms of chronic borate intoxication are different from those of the acute poisoning with which we are more familiar. The borax and honey preparations are highly dangerous and should no longer be manufactured or distributed for sale.