We all can contribute to training the new generation of pediatric hematologists

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/58088/1/21468_ftp.pd

Who will care for tomorrow's children with benign hematological conditions?

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/56165/1/21254_ftp.pd

Hematological monitoring during therapy with carbamazepine in children

No Abstract.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/50302/1/410130622_ftp.pd

Role of diradylglycerol formation in H2O2 and lactoferrin release in adherent human polymorphonuclear leukocytes

Polymorphonuclear leukocytes (PMNs) adherent to fibrinogen exhibit a delay in the release of H2O2 in response to fMLP. Previously, we demonstrated that H2O2 release in adherent PMNs coincides with the exocytosis of lactoferrin‐containing specific granules and activation of phospholipase D (PLD). We also found that chelation of intracellular calcium blocked both lactoferrin and H2O2 release in stimulated PMNs in spite of the fact that adhesion and spreading remained normal. Since diradylglycerol (DRG) formation has been implicated in PMN secretion and oxidant release, we determined the effect of intracellular calcium chelation on PLD activation and DRG formation to ascertain whether DRG formation was coupled to lactoferrin and H2O2 release. We observed that chelation of intracellular calcium with bis‐(O‐aminophenoxy)‐ethanol‐N,N;N’‐ tetraacetic add (BAPTA) prevented PLD activation as monitored by inhibition of phosphatidylethanol formation. Formation of DRG derived from phosphatidic acid (PA) was also inhibited in the presence of BAPTA. Following the addition of the calcium ionophore ionomycin to the BAPTA‐treated PMNs, lactoferrin and H2O2 release was coincident with the onset of DRG formation. Also the addition of sn‐1,2‐didecanoylglycerol to the BAPTA‐treated PMNs stimulated them to release H2O2. Our studies support the hypothesis that DRG derived from PLD activation is required for degranulation of specific granules and associated H2O2 release from adherent PMNs. J. Leukoc. Biol. 56: 105–109; 1994.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141596/1/jlb0105.pd

Human neutrophils permeabilized with digitonin respond with lysosomal enzyme release when exposed to micromolar levels of free calcium

We have recently reported that human neutrophils can be permeabilized with the cholesterol complexing agent saponin and that these cells can be induced to secrete the granule enzyme lysozyme in response to micromolar levels of free calcium. We now report that digitonin can be used in place of saponin and that it has several advantages. Permeabilization of human neutrophils was accomplished with 10 [mu]g/ml digitonin in a high potassium medium. Normally impermeant solutes such as [14C]sucrose and inulin[14C]carboxylic acid gained access to one half of the intracellular water space marked with [3H]H2O. Between 30 and 100% of the cytoplasmic enzyme, lactate dehydrogenase, leaked from the intracellular space. The permeabilization process and calcium-triggered granule secretion were critically dependent upon temperature, time and digitonin concentration. Permeabilized neutrophils secreted [beta]-glucuronidase, lysozyme and vitamin B-12 binding-protein, constituents of both azurophil and specific granules, when exposed to micromolar levels of free calcium. Release of specific granule constituents appeared to be more sensitive to free calcium than release from azurophil granules. Although the amount of permeabilization varied considerably with each batch of cells, release of these granule markers was a consistent finding. Release of granule markers was accompanied by resealing of the cells to high-molecular-weight (Mr > 5000) solutes. Electron microscopic evidence also suggested that granule and plasma membranes were intact following digitonin treatment and that fusion of these membranes occurred in response to calcium. These results suggest that elevation of intracellular free-calcium levels is a sufficient condition for lysosomal enzyme release.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26199/1/0000278.pd

Ultrastructural morphology and cytochemistry of iron-deficient polymorphonuclear leukocytes

Previous studies have documented decreased activities of certain enzymes and altered function in polymorphonuclear leukocytes (PMN) during iron deficiency. The present study was undertaken to determine if the enzymatic abnormalities could be correlated with morphologic or quantitative change in PMN granules. Ultrastructural examination of primary and secondary granules and assessment of the secondary granule components alkaline phosphatase and vicinal glycol-containing glycoconjugates was performed in rabbit bone marrow, peripheral blood, and peritoneal heterophils. In addition, biochemical quantifications of the secondary granule component alkaline phosphatase and the primary granule marker [beta]-glucuronidase were performed. The results confirmed that a marked, significant decrease in alkaline phosphatase occurs in iron-deficient animals; however, no biochemical decrease in [beta]-glucuronidase activity was observed. Ultrastructurally, PMN secondary granules of iron-deficient rabbits tended to be more numerous than in controls when examined with morphometric and glycoconjugate staining methods, but lacked staining in alkaline phosphatase preparations. These results demonstrate that iron-deficient rabbits produce normal to increased quantities of primary and secondary granules, despite a uniform deficiency of alkaline phosphatase, a secondary granule marker.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26267/1/0000352.pd

Changes in protein kinase C activity are associated with the differentiation of Friend erythroleukemia cells

We investigated the activity and cellular distribution of protein kinase C during the dimethylsulfoxide (DMSO) and hypoxanthine-induced differentiation of Friend murine erythroleukemia cells. Most of the cellular protein kinase C activity was found in the soluble fraction of unstimulated Friend cells. Within 15 min of the addition of DMSO or hypoxanthine, protein kinase C underwent a dramatic and prolonged reversal of this distribution which was accompanied by a gradual decline in total cellular protein kinase C activity over the ensuing 5 days. The loss of total activity was found to be dose dependent although maximal translocation from soluble to insoluble components occurred at even lower concentrations of the inducers tested. Two clones of Friend cells, selected for their failure to differentiate in response to DMSO, showed alterations in protein kinase C activity and/or distribution following DMSO addition when compared to wild-type Friend cells. These data show that different inducers of Friend cell differentiation have similar effects on cellular protein kinase C, that the protein kinase C changes accompanying this process are immediate but prolonged, and that changes in protein kinase C activity and distribution are associated with Friend cell differentiation.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26799/1/0000355.pd

Long-Term Effects of G-CSF Therapy in Cyclic Neutropenia

Cyclic neutropenia is a rare hematologic disease that is characterized by regular oscillations in blood neutrophil counts from normal levels (absolute neutrophil count [ANC], \u3e1.5×109 per liter) to severe neutropenia (ANC, \u3c0.2×109 per liter), usually with a cycle length of about 21 days.When patients with this disorder have neutropenia, they often have fever and mouth ulcers and are at risk for severe infections. Cyclic neutropenia is usually an autosomal dominant disorder caused by mutations in the gene encoding neutrophil elastase (ELANE)