Ultrasound-guided tandem placement for low-dose-rate brachytherapy in advanced cervical cancer minimizes risk of intraoperative uterine perforation.

OBJECTIVES: Tandem placement as part of low-dose-rate (LDR) brachytherapy boost for cervical cancer may be complicated by uterine perforation. The objective of this study was to describe a 10-year experience of using intraoperative ultrasound guidance in an attempt to minimize the risk of uterine perforation. METHODS: Operative and inpatient records were reviewed to identify cases in which intraoperative ultrasound guidance was employed in order to assist tandem placement, and to determine whether clinical or radiographic findings subsequently suggested uterine perforation. Demographic factors were collected in order to determine the baseline risk of perforation within this population. RESULTS: Between 1998 and 2008, 71 patients underwent 110 ultrasound-guided placements of tandem applicators. The median age was 48 (range, 26-88) years, and 20% were older than 60 years. Disease stage was FIGO IB1 (n = 10), IB2 (n = 13), IIA (n = 4), IIB (n = 19), IIIA (n = 2), IIIB (n = 16), IVA (n = 5) and IVB (n = 2). The median gravidity was 3 (range 1-10) and median parity was 3 (range 0-10). Seven patients had a preimplant history of pelvic infection, four had a history of intrauterine contraceptive device use, and 10 had a prior history of Cesarean section delivery. Only one patient experienced infection that may have been attributable to tandem placement-associated uterine perforation. At median survivor follow-up of 34 months, 19 patients had died. The estimated 3-year disease-free and overall survival rates for the entire population were 60% and 66%, respectively. CONCLUSIONS: Within the present population, intraoperative ultrasound guidance of tandem placement was associated with no confirmed cases of uterine perforation.

Formation of Charcot-Leyden crystals by human basophils.

Charcot-Leyden crystals (CLC) are currently believed to be unique to the eosinophil and a hallmark of active eosinophilic inflammation or proliferation. The distinctiveness of the CLC to the eosinophil was questioned in 1965 by Archer and Blackwood (9), but their demonstration of CLC formation in basophils was ignored and later dismissed (1) as being the result of eosinophil contamination of basophil-enriched cell suspensions. We reexamined this question and showed that basophils obtained from the peripheral blood of normal individuals form CLC and that basophils contain a protein that is immunochemically indistinguishable from eosinophil CLC protein. These conclusions are based upon the findings that (a) crystal formation in basophils was demonstrated by specific histochemical staining of crystal-containing cells in highly enriched basophil suspensions prepared by fluorescence-activated cell sorter (FACS) purification of surface IgE-positive cells, (b) that enrichment for surface IgE-positive cells (primarily basophils) by the FACS also enriched for cells staining positively by immunofluorescence for eosinophil CLC protein, and (c) that CLC protein was measured by radioimmunoassay in cell extracts prepared from purified basophil suspensions containing 97-99% basophils and absolutely no contaminating eosinophils. These basophil extracts contained a protein immunochemically indistinguishable from eosinophil CLC protein. Based upon these findings, the CLC or the protein comprising the crystal (lysophospholipase) can no longer be considered as distinctive to the eosinophil. We must now consider the possibility that the presence of CLC in tissues, sputum, or stool may also represent basophil involvement in disease processes.

Human eosinophil cationic protein. Molecular cloning of a cytotoxin and helminthotoxin with ribonuclease activity.

We have isolated a 725-bp full-length cDNA clone for the human eosinophil cationic protein (ECP). ECP is a small, basic protein found in the matrix of the eosinophil's large specific granule that has cytotoxic, helminthotoxic, and ribonuclease activity, and is a member of the ribonuclease multigene family. The cDNA sequence shows 89% sequence identity with that reported for the related granule protein, eosinophil-derived neurotoxin (EDN). The open reading frame encodes a previously unidentified 27-amino acid leader sequence preceding a 133-residue mature ECP polypeptide with a molecular mass of 15.6 kD. The encoded amino acid sequence of ECP shows 66% identity to that of EDN and 31% identity to that of human pancreatic ribonuclease, including conservation of the essential structural cysteine and cataytic lysine and histidine residues. mRNA for ECP was detected in eosinophil-enriched peripheral granulocytes and in a subclone of the promyelocytic leukemia line, HL-60, induced toward eosinophilic differentiation with IL-5. No ECP mRNA was detected in uninduced HL-60 cells, or in HL-60 cells induced toward monocytic differentiation with vitamin D3 or toward neutrophilic differentiation with DMSO. In contrast, mRNA for EDN was detected in uninduced HL-60 cells and was upregulated in HL-60 cells induced with DMSO. Despite similarities in sequence and cellular localization, these results suggest that ECP and EDN are subject to different regulatory mechanisms.

Activation of basophil and mast cell histamine release by eosinophil granule major basic protein.

Major basic protein (MBP) is a primary constituent of eosinophil granules. In this report, we demonstrate that MBP from human eosinophil granules initiates a nonlytic histamine release from human leukocytes. A direct effect of MBP on basophils was confirmed using purified human basophils. The kinetics of release were similar to those reported for poly-L-arginine, although MBP was less potent than poly-L-arginine of similar molecular weight. Reduction and alkylation of MBP diminished both the potency and efficacy of the molecule. Native MBP also stimulated histamine secretion from purified rat peritoneal mast cells in a manner characteristic of other polycations. These results emphasize the bidirectional nature of the basophil/mast cell-eosinophil regulatory axis.

Elevated serum levels in human pregnancy of a molecule immunochemically similar to eosinophil granule major basic protein.

We have shown that serum levels of a molecule immunochemically similar to eosinophil granule major basic protein (MBP) are elevated in pregnant women throughout gestation. MBP levels increase during gestation and plateau at approximately 7,500 ng/ml by the 20th wk (greater than 10-fold above normal). Levels return to normal after delivery, with a T1/2 of 13.7 d. The MBP in pregnancy serum is remarkably similar to the eosinophil granule MBP in that: (a) pregnancy MBP fully inhibits the binding of radiolabeled MBP standard in a double antibody radioimmunoassay; (b) this inhibition reaction is specific for human MBP because pregnancy serum produces no inhibition of the binding of radiolabeled guinea pig MBP in the guinea pig MBP radioimmunoassay; (c) in a two-site immunoradiometric assay for MBP, slopes of dose-response curves for pregnancy serum, purified MBP, and serum from a patient with hypereosinophilic syndrome are identical, and maximal binding is comparable; (d) reduction and alkylation of pregnancy sera increases measured MBP 100-fold, as previously shown for eosinophil granule MBP in serum; and (e) the MBP in pregnancy serum demonstrates the same pattern of heat lability as has been previously reported for MBP. Four observations have raised the possibility that the eosinophil is not the source of the MBP in pregnancy serum: (a) no correlation between serum MBP level and peripheral blood eosinophil count exists in pregnant women, in contrast to previous studies of patients with eosinophilia; (b) levels of three other eosinophil-associated proteins are normal or low in pregnancy sera, whereas the serum levels of these proteins are elevated in patients with eosinophilia; (c) the slopes of dose-response curves for pregnancy sera and MBP standards differ in the double antibody radioimmunoassay; and (d) the molecule in pregnancy serum elutes from Sephadex G-50 columns at the void volume, while eosinophil granule MBP and the MBP in serum of patients with eosinophilia elute at a volume consistent with the previously established molecular weight of 9,300. These findings suggest that the MBP in pregnancy serum is derived from a source other than the eosinophil.

Localization of eosinophil granule major basic protein in human basophils.

In experiments using an immunofluorescent method to localize human eosinophil granule major basic protein (MBP) in cells and tissues, a small number of cells stained for MBP that subsequently could not be identified as eosinophils. Because the Charcot-Leyden crystal protein, another eosinophil protein, was recently identified in basophils, we tested whether MBP might also be a constituent of blood basophils. Highly purified, eosinophil-free basophil suspensions were prepared using the fluorescence-activated cell sorter (FACS) to sort basophil-containing mononuclear cell preparations stained with fluorescein-conjugated sheep IgG anti-human IgE antibody. Using these FACS-purified basophils, we found that: (a) enrichment for surface IgE-positive cells (greater than 95% basophils) by FACS also enriched for cells staining for MBP by immunofluorescence; (b) MBP appeared to be localized in the histamine-, heparin-containing granules; (c) significant quantities of MBP were measurable by radioimmunoassay (RIA) in freeze-thaw detergent extracts of purified basophils; and (d) RIA dose-response curves for extracts of purified eosinophils and basophils had identical slopes. The MBP content of basophils from normal individuals averaged 140 ng/10(6) cells, whereas purified eosinophils from normal donors and patients with the hyper-eosinophilic syndrome averaged 4,979 and 824 ng/10(6) cells, respectively. MBP was also detected by immunofluorescence and RIA in cells obtained from a patient with basophil leukemia, although the MBP content for basophil leukemia cells was lower than that for normal basophils. We conclude that basophils contain a protein that is immunochemically indistinguishable from eosinophil granule MBP.

Cytoplasmic lipid bodies of neutrophils: formation induced by cis-unsaturated fatty acids and mediated by protein kinase C.

Lipid bodies, nonmembrane-bound cytoplasmic inclusions, serve as repositories of esterified arachidonate and are increased in cells associated with inflammatory reactions. We have evaluated stimuli and mechanisms responsible for lipid body formation within human polymorphonuclear leukocytes (PMNs). Arachidonic acid and oleic acid stimulated dose-dependent formation of lipid bodies over 0.5-1 h. Other C20 and C18 fatty acids were less active and demonstrated rank orders as follows: cis-unsaturated fatty acids were much more active than trans-fatty acids, and activity diminished with decreasing numbers of double bonds. Lipid bodies elicited in vitro with cis-fatty acids were ultrastructurally identical to lipid bodies present in PMNs in vivo. Lipid body induction was not because of fatty acid-elicited oxidants or fatty acid-induced ATP depletion. Cis-fatty acid-induced activation of protein kinase C (PKC) was involved in lipid body formation as evidenced by the capacity of other PKC activators, 1-oleoyl-2-acetyl-glycerol and two active phorbol esters, phorbol myristate acetate, and phorbol 12,13 dibutyrate, but not an inactive phorbol, to induce lipid body formation. The PKC inhibitor, 1-O-hexadecyl-2-O-methyl-glycerol, inhibited PMN lipid body formation induced by oleic and arachidonic acids and by 1-oleoyl-2-acetyl-glycerol and phorbol myristate acetate. Other PKC inhibitors (staurosporine, H-7) also inhibited lipid body formation. Formation of lipid bodies in PMNs is a specific cellular response, stimulated by cis-fatty acids and diglycerides and apparently mediated by PKC, which results in the mobilization and deposition of lipids within discrete, ultrastructurally defined cytoplasmic domains.

Human eosinophil-granule major basic protein and synthetic polycations induce airway hyperresponsiveness in vivo dependent on bradykinin generation.

In the current series of experiments we investigated the role of bradykinin in airway hyperresponsiveness induced by human eosinophil-granule major basic protein (MBP). Bronchoalveolar lavage was performed after intratracheal instillation of MBP or poly-L-lysine in anesthetized, intubated rats, and levels of immunoreactive kinins and kallikrein-like activity were determined. Both MBP and poly-L-lysine induced a three- and eightfold increase in levels of kallikrein-like activity and i-kinins, respectively. To determine whether kinin production is required for the development of airway hyperresponsiveness induced by cationic proteins, dose-response curves to methacholine were constructed before and 1 h after intratracheal instillation of either MBP or poly-L-lysine (100 micrograms). MBP and poly-L-lysine induced an increase in airway responsiveness, which was inhibited by pretreatment with a selective BK-2 receptor antagonist, NPC 17713 (250 micrograms/ml). Our results demonstrate that MBP and poly-L-lysine activate kallikrein and stimulate the generation of i-kinins in vivo, an effect that may be related to the cationic charge of these proteins. Furthermore, the ability of these proteins to increase airway responsiveness appears to be dependent on the generation of i-kinins.

Crystal structure of human Charcot-Leyden crystal protein, an eosinophil lysophospholipase, identifies it as a new member of the carbohydrate-binding family of galectins.

BACKGROUND: The Charcot-Leyden crystal (CLC) protein is a major autocrystallizing constituent of human eosinophils and basophils, comprising approximately 10% of the total cellular protein in these granulocytes. Identification of the distinctive hexagonal bipyramidal crystals of CLC protein in body fluids and secretions has long been considered a hallmark of eosinophil-associated allergic inflammation. Although CLC protein possesses lysophospholipase activity, its role(s) in eosinophil or basophil function or associated inflammatory responses has remained speculative. RESULTS: The crystal structure of the CLC protein has been determined at 1.8 A resolution using X-ray crystallography. The overall structural fold of CLC protein is highly similar to that of galectins -1 and -2, members of an animal lectin family formerly classified as S-type or S-Lac (soluble lactose-binding) lectins. This is the first structure of an eosinophil protein to be determined and the highest resolution structure so far determined for any member of the galectin family. CONCLUSIONS: The CLC protein structure possesses a carbohydrate-recognition domain comprising most, but not all, of the carbohydrate-binding residues that are conserved among the galectins. The protein exhibits specific (albeit weak) carbohydrate-binding activity for simple saccharides including N-acetyl-D-glucosamine and lactose. Despite CLC protein having no significant sequence or structural similarities to other lysophospholipase catalytic triad has also been identified within the CLC structure, making it a unique dual-function polypeptide. These structural findings suggest a potential intracellular and/or extracellular role(s) for the galectin-associated activities of CLC protein in eosinophil and basophil function in allergic diseases and inflammation.

Cost-effectiveness of catheter ablation in patients with ventricular tachycardia.

BACKGROUND: This study evaluated the cost-effectiveness of catheter ablation therapy versus amiodarone for treating ventricular tachycardia (VT) in patients with structural heart disease. The analysis used a societal perspective for a hypothetical cohort of VT patients with implantable cardioverter-defibrillators, who were experiencing frequent shocks. METHODS AND RESULTS: We calculated incremental cost-effectiveness of ablation relative to amiodarone over 5 years after treatment initiation. Event probabilities were from the Chilli randomized clinical trial (Chilli Cooled Ablation System, Cardiac Pathways Corporation, Sunnyvale, Calif), the literature, and a consensus panel. Costs were from 1998 national Medicare reimbursement schedules. Quality-of-life weights (utilities) were estimated using an established preference measurement technique. In a hypothetical cohort of 10 000 patients, 5-year costs were higher for patients undergoing ablation compared with amiodarone therapy ($21 795 versus $19 075). Ablation also produced a greater increase in quality of life (2.78 versus 2.65 quality-adjusted life-years [QALYs]). This yielded a cost-effectiveness ratio of $20 923 per QALY gained for ablation compared with amiodarone. Results were relatively insensitive to assumptions about ablation success and durability. In less severe patients with good ejection fractions who suffer their first VT episode, the incremental cost-effectiveness ratio was $6028 per QALY gained. These cost-effectiveness ratios are within the range generally thought to warrant technology adoption. CONCLUSIONS: This study demonstrates that, from a societal perspective, catheter ablation appears to be a cost-effective alternative to amiodarone for treating VT patients.

Hyperpolarization-activated chloride currents in Xenopus oocytes.

During hyperpolarizing pulses, defolliculated Xenopus oocytes have time- and voltage-dependent inward chloride currents. The currents vary greatly in amplitude from batch to batch; activate slowly and, in general, do not decay; have a selectivity sequence of I- > NO3- > Br- > Cl- > propionate > acetate; are insensitive to Ca2+ and pH; are blocked by Ba2+ and some chloride channel blockers; and have a gating valence of approximately 1.3 charges. In contrast to hyperpolarization-activated chloride currents induced after expression of phospholemman (Palmer, C. J., B. T. Scott, and L. R. Jones. 1991. Journal of Biological Chemistry. 266:11126; Moorman, J. R., C. J. Palmer, J. E. John, J. E. Durieux, and L. R. Jones. 1992. 267:14551), these endogenous currents are smaller; have a different pharmacologic profile; have a lower threshold for activation and lower voltage-sensitivity of activation; have different activation kinetics; and are insensitive to pH. Nonetheless, the endogenous and expressed current share striking similarities. Recordings of macroscopic oocyte currents may be inadequate to determine whether phospholemman is itself an ion channel and not a channel-modulating molecule.

Interleukin-5 receptor alpha subunit gene regulation in human eosinophil development: identification of a unique cis-element that acts lie an enhancer in regulating activity of the IL-5R alpha promoter.

Further functional and biochemical characterization of the nuclear factor(s) which interacts with the EOS1 enhancer-like element in the IL-5R alpha promoter is currently in progress. Since different transcription factors recognize and interact with DNA in distinct fashions and with distinct structural motifs, we have modeled potential binding of the EOS1 factor to its cis-element based upon its methylation interference pattern (Fig. 2), using a cylindrical DNA helical projection (Fig. 6). Over a length of two helical turns, all nuclear protein contacts indicated by methylation interference map to one side of the DNA helix, suggesting that EOS1 binds in the major groove, across the minor groove, and on only one side of the helix. Further review of the model also reveals a potential diad symmetry for the binding site, suggestive of binding by a homodimer and consistent with the formation of the two DNA-protein complexes in our electrophoretic mobility shift experiments that could represent interactions with monomer versus dimer. Comparison of the EOS1 binding motif to similar models for the binding of other transcription factor families for which structural crystallographic and/or binding data is available suggests a similarity of the EOS1 complex to that of the bacterial helix-turn-helix phage lambda and 434 repressor-operator complexes, and the Cys4 zinc finger glucocorticoid response element (GRE) DNA-binding motifs, all of which show similar diad symmetry and binding in the major groove on one side of the DNA. The possibility that EOS1 functions as a GRE is being investigated, especially since there is a consensus AP-1 site at bp -440 to -432 of the IL-5R alpha promoter, immediately adjacent to the EOS1 binding site (see Fig. 5 in reference [36]) and AP-1/GRE interactions have been identified for composite response elements in the regulation of a number of different genes. The identification or cloning of EOS1, a potentially novel and eosinophil lineage-active transcription factor, should enhance our understanding of the processes involved in eosinophil development in particular and myeloid lineage commitment and differentiation in general.

Models of lineage switching in hematopoietic development: a new myeloid-committed eosinophil cell line (YJ) demonstrates trilineage potential.

A new human leukemia cell line with an eosinophilic phenotype, designated YJ, was established from the peripheral blood cells of a patient with chronic myelomonocytic leukemia (CMMoL) with eosinophilia. When cultured in RPMI 1640 medium containing 10% fetal bovine serum, most YJ cells were myeloblastoid with a small number of the cells having eosinophilic granules. Cell surface markers in the YJ cells were positive for CD33 and were negative for CD34, CD16 and CD23. The eosinophilic characteristics of YJ cells were confirmed by histochemical staining with Fast-Green/Neutral-Red and by the expression of mRNAs for eosinophil-associated granule proteins, eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), eosinophil peroxidase (EPO), and major basic protein (MBP), and for the Charcot-Leyden crystal (CLC) protein. The YJ cells could be induced towards monocytic differentiation by stimulation with phorbol 12-myristate 13-acetate (PMA). The monocytic characteristics of YJ cells treated with PMA were confirmed by morphological analysis with alpha-naphthyl butyrate esterase staining, by CD14 expression, and by increased expression of Egr-1 mRNA. Furthermore, YJ cells could be differentiated towards the neutrophil lineage by stimulation with all-trans retinoic acid (RA). YJ cells treated in vitro with 2 microM RA differentiated into metamyelocytes and band neutrophils, and increased the number of nitroblue tetrazolium (NBT)-positive cells and increased gp91phox mRNA expression. Thus, the YJ cell line exhibited eosinophilic characteristics, but was able to differentiate to the monocytic or neutrophilic lineages in response to PMA or RA, respectively. The expression of genes for transcription factors involved in myeloid differentiation was evaluated by Northern blot analysis. Increased expression of Egr-1 was observed with macrophage differentiation. In contrast, increased expressions of C/EBPbeta and MZF-1 mRNA occurred with neutrophilic differentiation. The YJ cell line should be useful for elucidating the molecular mechanisms governing lineage switching from the eosinophil to monocytic or neutrophil lineages.

Eosinophil granule cationic proteins: major basic protein is distinct from the smaller subunit of eosinophil peroxidase.

Major basic protein and eosinophil peroxidase are predominant cationic proteins in the cytoplasmic granules of human eosinophilic leukocytes. Each of these proteins has been purified, and major basic protein and the lower molecular weight subunit of eosinophil peroxidase have been found to comigrate on polyacrylamide gel electrophoresis in sodium dodecyl sulfate with similar apparent molecular weights of about 14,700. Because previous molecular weight estimates for these proteins have not recognized the similar molecular weights of these two cationic eosinophil granule constituents, we have evaluated the possible relatedness of these proteins. Upon protein sequence analyses, it was found that the N-terminal 20 amino acid residues of each of these two purified polypeptides differed. These findings established that major basic protein and the smaller subunit of eosinophil peroxidase, although of comparable molecular weights, are two distinct proteins within the cytoplasmic granules of human eosinophils.

The gene for human eosinophil Charcot-Leyden crystal protein directs expression of lysophospholipase activity and spontaneous crystallization in transiently transfected COS cells.

Expression of the gene encoding human eosinophil lysophospholipase, the Charcot-Leyden crystal (CLC) protein, was studied in transiently transfected COS cells. Recombinant CLC (rCLC) protein expression was demonstrated both by Western blot and radioimmunoassay inhibition analyses of transfected COS cell extracts and by immunofluorescent staining and ultrastructural immunogold analyses of intact cells. The rCLC protein was immunochemically indistinguishable from native eosinophil-derived CLC protein, and each transfected COS cell expressed approximately 11 pg of rCLC protein as determined by radioimmunoassay and assessment of transfection efficiency. Immunofluorescent microscopy and ultrastructural immunogold analyses localized rCLC protein to the nucleus, cytoplasm, and plasma membrane of COS cells. Lysates from transfected COS cells producing CLC protein expressed significant lysophospholipase activity. Furthermore, rCLC protein expressed in COS cells spontaneously formed the distinctive intracytoplasmic and intranuclear hexagonal bipyramidal crystals characteristic of the native eosinophil and basophil-derived protein. Expression of the CLC gene confirms the authenticity of the CLC cDNA, the expression of lysophospholipase activity by this unique eosinophil and basophil constituent, and will facilitate the routine purification of the active enzyme for in vitro and animal model studies of its role (or roles) in eosinophil and basophil associated allergic inflammation and eosinophil-parasite interactions.

Cytokine induction of granule protein synthesis in an eosinophil-inducible human myeloid cell line, AML14.

Study of eosinophil growth and differentiation has been hampered by the difficulty of obtaining adequate numbers of highly purified eosinophil progenitors or mature eosinophils for analysis. The AML14 myeloid leukemia cell line has the unusual ability to exhibit eosinophilic differentiation in response to stimulation by combinations of the eosinophil-active cytokines interleukin-3 (IL-3), granulocyte-macrophage colony-stimulating factor, and IL-5. We now demonstrate that AML14 cells can be stimulated by a combination of these cytokines to produce mRNA encoding all the eosinophil granule proteins, including major basic protein (MBP), eosinophil peroxidase (EPO), eosinophil cationic protein (ECP), eosinophil-derived neurotoxin (EDN), and the Charcot-Leyden crystal (CLC) protein (eosinophil lysophospholipase). The production of the mature proteins was demonstrated by Western blotting, and ultrastructural analysis demonstrated the presence of immature secondary granules in cells that had been induced to differentiate to eosinophils. These findings demonstrate the utility of the AML14 cell line as a model for the study of cytokine induction of eosinophil growth and differentiation.

Charcot-Leyden crystal protein in the degranulation and recovery of activated basophils.

The Charcot-Leyden crystal (CLC) protein, a prominent cell constituent unique to eosinophils and basophils, possesses lysophospholipase activity. This activity and the extracellular deposition and formation of CLC in tissues and body fluids in association with eosinophils suggest an extracellular function for this protein in inflammation. During degranulation, basophils release granule-derived mediators of inflammation. We postulated that CLC protein, localized in part to the basophil granule, might be released along with other mediators during this process. The extracellular release of CLC protein was studied during the degranulation of basophils stimulated by anti-immunoglobulin E (anti-IgE), N-formyl-methionyl-leucyl-phenylalanine (fMLP), phorbol myristate acetate, eosinophil major basic protein (MBP), and calcium ionophore A23187. Histamine release was used as a marker of basophil degranulation; its release was measured utilizing the fluorometric technique. CLC protein was not released into the supernatant during this process as determined by radioimmunoassay. CLC protein in the extracellular space, either as intact crystals or aggregates, was undetectable by indirect immunofluorescent staining of basophils activated with either anti-IgE or fMLP. However, upon activation, the immunofluorescent cytoplasmic and nuclear staining pattern for CLC protein was significantly altered. Decreased cytoplasmic staining and persistent or increased nuclear staining for CLC protein were observed after activation, with recovery of the preactivation, unstimulated cellular staining pattern at 30 and 45 min after stimulation with fMLP and anti-IgE, respectively. These findings suggest that CLC protein functions intracellularly in basophils during the process of activation, degranulation, and recovery. The potential nuclear function(s) of this lysophospholipase in the basophil requires further investigation.

Evidence for secretion of human eosinophil granule major basic protein and Charcot-Leyden crystal protein during eosinophil maturation.

Prior electron microscopic studies have suggested that immature eosinophils degranulate during normal maturation in human bone marrow. This hypothesis was tested by measuring levels of eosinophil granule major basic protein (MBP) and Charcot-Leyden crystal (CLC) protein in bone marrow sinusoidal blood. MBP and CLC protein levels were elevated initially in bone marrow sinusoidal blood from normal volunteers when compared with peripheral blood, and levels of both proteins decreased during serial sampling; CLC protein levels remained significantly elevated, while MBP levels declined to equal those of peripheral blood. To investigate whether MBP and CLC protein were secreted during eosinophil maturation, bone marrow cells were cultured in soft agar; MBP and CLC protein levels were measured in culture supernatants by RIA. There was a significant positive correlation between eosinophil colony growth and levels of each protein. Electron micrographs of cells in soft agar colonies provided ultrastructural evidence for secretion of granule products by immature eosinophils. These results support prior observations that eosinophil promyelocytes degranulate during maturation.

Human cell line that differentiates to all myeloid lineages and expresses neutrophil secondary granule genes.

The aim of this study was to characterize a human leukemic cell line that appears capable of spontaneous differentiation to all myeloid lineages. The MPD cell line was derived using standard tissue culture techniques from the peripheral blood of a patient with an aggressive nonchronic myelogenous leukemia myeloproliferative disorder. Immunophenotyping, cytogenetic analysis, reverse transcriptase polymerase chain reaction, Northern blotting, immunoblotting, and colony assays were used to characterize the line and to assess its ability to express lineage-specific genes representative of advanced differentiation.Light microscopic morphologic analysis of the MPD cell line suggests that it has the unique property of spontaneous differentiation to mature-appearing neutrophils, macrophages, eosinophils, and basophils in proportions that approximate those found in normal bone marrow or peripheral blood. It was demonstrated that this cell line is capable of producing lineage-specific mRNA and granule proteins of at least two myeloid lineages, neutrophil and eosinophil, including neutrophil secondary granule proteins, which are not expressed in other available human cell lines. MPD cells were found to be capable of producing differentiated myeloid colonies (neutrophil, eosinophil, macrophge, mixed) in semisolid medium. The ability of MPD cells to express genetic programs associated with advanced differentiation of multiple myeloid lineages will make it a valuable tool for the study of the processes underlying lineage commitment and the regulation of expression of lineage-specific genes.