Granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor and macrophage colony-stimulating factor in the treatment of acute myeloid leukemia and acute lymphoblastic leukemia

To explore the role of perfectionism across anxiety disorders, 175 patients with either panic disorder (PD), obsessive compulsive disorder (OCD), social phobia, or specific phobia, as well as 49 nonclinical volunteers, completed two measures [Frost, R. O., Marten, P., Lahart, C., & Rosenblate, R., (1990). The dimensions of perfectionism. Cognitive Therapy and Research, 14, 449-468; Hewitt, P. L., & Flett, G. L., (1991). Perfectionism in the self and social contexts: Conceptualization, assessment and association with psychopathology. Journal of Personality and Social Psychology, 60, 456-470.] that assess a total of nine different dimensions of perfectionism. Relative to the other groups, social phobia was associated with greater concern about mistakes (CM), doubts about actions (DA), and parental criticism (PC) on one measure and more socially prescribed perfectionism (SP) on the other measure. OCD was associated with elevated DA scores relative to the other groups. PD was associated with moderate elevations on the CM and DA subscales. The remaining dimensions of perfectionism failed to differentiate among groups. The clinical implications of these findings are discussed.     

Bioactive tumour necrosis factor alpha but not granulocyte-macrophage colony-stimulating factor correlates inversely with Langerhans''s cell numbers in skin tumours

Human cytomegalovirus (CMV) infection of smooth muscle cells generates reactive oxygen species (ROS) and thereby activates nuclear factor kappaB (NFkappaB), which causes expression of viral and cellular genes involved in immune and inflammatory responses. These changes could account for the mounting evidence suggesting that CMV may contribute causally to restenosis and atherosclerosis. We found that CMV induces ROS, at least partly, through a cyclooxygenase-2 (COX-2)-dependent pathway. Moreover, the viral immediate-early (IE) gene products, IE72 and IE84, have the capacity to transactivate the COX-2 promoter. Aspirin and indomethacin, both cyclooxygenase inhibitors as well as direct ROS scavengers, reduce CMV-induced ROS, probably through both of these activities. Sodium salicylate also has antiviral effects as the result of its potent antioxidant properties. Furthermore, by reducing ROS, aspirin and sodium salicylate inhibit CMV-induced NFkappaB activation, the ability of IE72 to transactivate its promoter, CMV IE gene expression after infection of SMCs, and CMV replication in SMCs. This is the first time aspirin has been shown to have antiviral effects. Thus, it is possible that aspirin has previously unrecognized therapeutic effects in various clinical situations, such as in viral infections (when used as an antipyretic agent) and in atherosclerosis (when used as an antiplatelet agent).     

Critical role of Lyn kinase in inhibition of neutrophil apoptosis by granulocyte-macrophage colony-stimulating factor

The signal pathway for control of apoptosis in human neutrophils is currently unknown. In this study, we provide the first evidence that a Src family tyrosine kinase, Lyn, plays a key role in inhibition polymorphonuclear (PMN) cell death. Several nuclear proteins associated with apoptosis, i.e., p53, cdc2, and Rb, were absent from PMN. Bcl-2, known to inhibit apoptosis, was also not expressed. Programmed cell death that rapidly occurred in PMN could be arrested by granulocyte-macrophage CSF (GM-CSF), but this activation did not induce p53, cdc2, retinoblastoma, or Bcl-2 expression. Instead, GM-CSF produced a rapid activation of Lyn and Hck, but not Fgr, tyrosine phosphorylation within 1 min. Co-immunoprecipitation studies indicated that only Lyn, but not Hck, was physically coupled to GM-CSF receptor. By histologic assessment and evaluation of DNA fragmentation, only antisense Lyn, but not antisense Hck or antisense Fgr, could reverse the cell survival advantage provided by GM-CSF. Therefore, the physical coupling of Lyn to GM-CSF receptor and its early activation are required for inhibition or delay of apoptosis in PMN.     

Cooperative effects of interleukin-3 (IL-3), IL-5, and granulocyte-macrophage colony-stimulating factor: a new myeloid cell line inducible to eosinophils

The cytokines interleukin-3 (IL-3); IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) are known to contribute to the proliferation and differentiation of eosinophil progenitors. Recently, it was determined that the cellular receptors for these three cytokines share a common beta-chain while having unique alpha-chains. Thus, there is considerable interest in how these cytokines and their receptors interact in promoting production of eosinophils. We have established a cell line (AML14) from a patient with acute myelogenous leukemia that will consistently exhibit eosinophilic differentiation in suspension in response to IL-3, IL-5, and GM-CSF. Proliferation with only modest differentiative effects was observed in response to a single cytokine. Combinations of two cytokines gave variable results, with GM-CSF + IL-3 and IL-3 + IL-5 causing more proliferation than a single cytokine but little more differentiation. The combination of GM-CSF + IL-5 caused marked enhancement of eosinophilic differentiation with only modest augmentation of proliferation. The combination of all three cytokines was most effective in stimulating both proliferation and eosinophilic differentiation (up to 70% of cells) of AML14 cells. Specific binding of GM-CSF and IL-5 to AML14 cells can be conveniently studied by flow cytometric methods, and cross-competition of these two cytokines for their respective receptors was demonstrated. IL-3 was shown to partially compete for IL-5 binding on AML14 cells. Although specific IL-3 binding could not be demonstrated by flow cytometry, mRNA for the alpha-chains of the IL-3, IL-5, and GM-CSF receptors and the beta-chain common to all three receptors was detected in AML14 cells. The AML14 cell line may be a useful model for the study of cooperative interactions of IL-3, IL-5, GM-CSF, and their respective receptors in the promotion of eosinophil progenitor growth and differentiation.     

Diphtheria toxin fused to granulocyte-macrophage colony-stimulating factor eliminates acute myeloid leukemia cells with the potential to initiate leukemia in immunodeficient mice, but spares normal hemopoietic stem cells

We studied the cell kill induced by granulocyte-macrophage colony-stimulating factor (GM-CSF ) fused to Diphtheria Toxin (DT-GM-CSF ) in acute myeloid leukemia (AML) samples and in populations of normal primitive hemopoietic progenitor cells. AML samples from three patients were incubated in vitro with 100 ng/mL DT-GM-CSF for 48 hours, and AML cell kill was determined in a proliferation assay, a clonogenic assay colony-forming unit-AML (CFU-AML) and a quantitative long-term bone marrow (BM) culture ie, the leukemic-cobblestone area forming cell assay (L-CAFC). To measure an effect on cells with in vivo leukemia initiating potential DT-GM-CSF exposed AML cells were transplanted into immunodeficient mice. In two out of three samples it was shown that all AML subsets, including those with long-term abilities in vivo (severe combined immunodeficient mice) and in vitro (L-CAFC assay) were reduced in number by DT-GM-CSF. Cell kill induced by DT-GM-CSF could be prevented by coincubation with an excess of GM-CSF, demonstrating that sensitivity to DT-GM-CSF is specifically mediated by the GM-CSF receptor. Therefore, binding and internalization of GM-CSF probably occur in immature AML precursors of these two cases of AML. The third AML sample was not responsive to either GM-CSF or DT-GM-CSF. The number of committed progenitors of normal bone marrow (burst-forming unit-erythroid, colony-forming unit granulocyte- macrophage, and cobble stone area forming cell [CAFC] week 2) and also the number of cells with long-term repopulating ability, assayed as week 6 CAFC, were unchanged after exposure to DT-GM-CSF (100 ng/mL, 48 hours). These studies show that DT-GM-CSF may be used to eliminate myeloid leukemic cells with long-term potential in vitro and in immunodeficient mice, whereas normal hemopoietic stem cells are spared.     

Adenovirus-mediated granulocyte-macrophage colony-stimulating factor improves lung pathology of pulmonary alveolar proteinosis in granulocyte-macrophage colony-stimulating factor-deficient mice

Mutation of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene by homologous recombination causes progressive pulmonary alveolar proteinosis (PAP) in GM-CSF-deficient mice (GM-/-). The present study tested whether adenovirus-mediated expression of GM-CSF alters the progression of PAP in GM-/- mice. Adult mice were pretreated with an anti-T cell receptor (TCR) antibody to block T cell-mediated immune response, followed by intratracheal instillation of deltaE1-E3 replication-deficient adenovirus expressing mouse GM-CSF (Av1mGM). Mice were killed 1, 3, and 5 weeks after treatment to assess lungs for GM-CSF, surfactant protein B (SP-B), alveolar macrophage maturation, and type II cell proliferation. GM-CSF was detected in BAL fluid from GM-/- mice 1 week after Av1mGM treatment, and GM-CSF mRNA was detected by RT-PCR through 5 weeks. Five weeks after Av1mGM treatment, PAP was improved and SP-B decreased as assessed by ELISA and immunostaining. Increased numbers of alveolar macrophages stained with alpha-naphthyl acetate esterase (alpha-NAE) following treatment with Av1mGM. Local expression of GM-CSF with a recombinant adenovirus ameliorated PAP in the GM-/- mice in association with enhanced maturation of alveolar macrophages.     

Keratinocyte growth stimulation by granulocyte-macrophage colony-stimulating factor (GM-CSF)

A comprehensive review of ultrasonography of the knee is presented and includes the choice of equipment and best patient positioning as well as a review of the normal anatomy and major disorders involving the knee, menisci and ligaments.     

Granulocyte and granulocyte-macrophage colony-stimulating factors, their receptors and interleukin-3 levels in newborns

OBJECTIVE: The objective of this study was to determine the incidence of macrosomia in infants of diabetic mothers (IDM) and to analyze its possible correlation with insulin, C-peptide, growth hormone (GH) and IGF-I levels in umbilical cord blood. PATIENTS AND METHODS: A prospective study of 58 IDM and 58 control newborns (33 males and 25 females in both groups) was carried out. RESULTS: The incidence of macrosomia was 25.8% in the IDM group and 61.5% in the IIDDM group (infant of insulin-dependent diabetic mother) compared to 5% in the control group. There was a positive correlation between maternal Hgb Alc levels in the third trimester of gestation and insulin and C-peptide levels with newborn weight in the IDM group (especially in the IIDDM group). IGF-I levels were positively correlated with newborn weight in both control and IDM groups. There was no correlation between GH and IGF-I levels in any group.     

Focal adhesion kinase in integrin signaling

Using radiotelemetry, this study aimed to evaluate the influence of tobacco smoke on heart rate (H), body temperature (T) and locomotor activity (A) daily rhythms in rats. The tobacco smoke intoxication was produced with a smoking apparatus. H, T, and A data were captured by radiotelemetry. The study was divided into three periods: a 1-week control period (P1), a 1-week stress period (P2), in order to evaluate the stress induced by the animals' restraint in the smoking apparatus, and a 1-week daily tobacco smoke intoxication period (P3). For P1, P2, and P3, a power spectrum analysis was applied in order to determine the dominant period of rhythmicity. Then, characteristics of the rhythms were determined by cosinor analysis. Statistical comparisons were done by ANOVA. Power spectrum analysis showed that neither stress nor tobacco suppressed the daily rhythmicity. Cosinor revealed some modifications: H amplitude was decreased during P2 and P3 with a greater reduction during P3, while T and A amplitudes were decreased during P2 and P3 without difference between P2 and P3. T acrophase was delayed during P2, while A acrophase was delayed during P2 and P3 without any difference between P2 and P3. These perturbations may reflect the effects of stress and tobacco on the suprachiasmatic nucleus by a dopaminergic mechanism.     

Cytokine-specific activation of distinct mitogen-activated protein kinase subtype cascades in human neutrophils stimulated by granulocyte colony-stimulating factor, granulocyte-macrophage colony-stimulating factor, and tumor necrosis factor-alpha

To clarify the differences of the signaling pathways used by granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and tumor necrosis factor- (TNF), we investigated activation of mitogen-activated protein kinase (MAPK) subtype cascades in human neutrophils stimulated by these cytokines. G-CSF exclusively tyrosine-phosphorylated extracellular signal-regulated kinase (ERK). GM-CSF tyrosine-phosphorylated ERK strongly and p38 MAPK weakly, whereas TNF tyrosine-phosphorylated p38 MAPK strongly and ERK weakly. Consistent with these findings, MEK, an upstream kinase of ERK, was phosphorylated by G-CSF, GM-CSF, and TNF, whereas MKK3/MKK6, an upstream kinase of p38 MAPK, was phosphorylated by GM-CSF and TNF, but not by G-CSF. The potency of these cytokines to phosphorylate ERK and MEK was GM-CSF > G-CSF > TNF, whereas that to phosphorylate p38 MAPK and MKK3/MKK6 was TNF > GM-CSF. C-Jun amino-terminal kinase (JNK) was not tyrosine-phosphorylated by any cytokine despite the existence of JNK proteins in human neutrophils, whereas it was tyrosine-phosphorylated by TNF in undifferentiated and all-trans retinoic acid-differentiated HL-60 cells. Increased phosphorylation of ERK or p38 MAPK was detected within 1 to 5 minutes after stimulation with each cytokine and was dependent on the concentrations of cytokines used. MEK inhibitor (PD98059) reduced tyrosine phosphorylation of ERK, but not p38 MAPK, induced by G-CSF, GM-CSF, or TNF. GM-CSF- or TNF-induced superoxide (O2-) release was inhibited by p38 MAPK inhibitor (SB203580) in a dose-dependent manner, suggesting the possible involvement of p38 MAPK in GM-CSF- or TNF-induced O2- release. The results indicate that G-CSF, GM-CSF, and TNF activate the overlapping but distinct MAPK subtype cascades in human neutrophils and suggest that the differential activation of ERK and p38 MAPK cascades may explain the differences of the effects of these cytokines on human neutrophil functions.     

Clinical use of granulocyte-macrophage colony-stimulating factor and granulocyte colony-stimulating factor in neutropenia associated with malignancy

G-CSF and GM-CSF have been shown in each clinical setting to reduce the duration of neutropenia, with the exception of the scant data available in the unrelated bone marrow transplant setting. These growth factors also have been shown to have no leukemogenic effect during the observation periods of the trials discussed. In MDS, one major randomized trial has demonstrated a reduction in incidence of infection. This has not yet been demonstrated in AML and allogeneic BMT. Data from ongoing and future trials will be helpful in elucidating their effect on treatment-related morbidity and overall survival.     

Granulocyte-macrophage colony-stimulating factor and interleukin-3 potentiate interferon-gamma-mediated endothelin production by human monocytes: role of protein kinase C

Monocytic cells have been shown to produce endothelin, a potent vasoconstrictor molecule with immune modulating properties. The signalling mechanisms involved in this response are presently unclear. Monocytes are also believed to play an important role in inflammatory bowel disease (IBD). The objective of this study was to characterize the role of various cytokines, bacterial lipopolysaccharide (LPS) and colony-stimulating factors on the production of endothelin (ET) by freshly isolated human monocytes. Compelling circumstantial evidence exists for the conditions being investigated occurring in inflamed bowel mucosa to where monocytes migrate. Whereas LPS stimulated the release of 7 pg ET/2x106 cells in 40 hr, interferon-gamma (IFN-gamma) stimulated 45 pg ET/2x106 cells in 40 hr. There was an additive response when the two stimuli were employed together. Significantly the addition of either granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3 (IL-3) effected a two- to threefold, dose-dependent increase in the production of ET. Production of endothelin was reproducibly blocked by the addition of the protein kinase C (PKC) inhibitors staurosporine and H7, as well as by the protein synthesis inhibitor cycloheximide. Assessment of the activities of the alpha and beta isoforms of conventional protein kinase C (PKC), as determined by MonoQ column fractionated calcium and lipid activatible phosphotransferase activity towards myelin basic protein (MBP) revealed an additive effect of using LPS, IFN-gamma and GM-CSF, which was even greater than that demonstrated for phorbol myristate acetate (PMA). Additionally the secretion of ET by monocytes from Crohn's disease patients (in remission) was analysed and compared with an age-matched control group. There was no significant difference between the two. These results: (1) demonstrate an important synergistic role for GM-CSF and IL-3 in the predominantly IFN-gamma-mediated ET production by normal human monocytes; (2) indicate a possible role for the protein kinase C signalling pathway in this response; and (3) argue against a primary abnormality of ET production in peripheral monocytes from patients with Crohn's disease.     

Hydrocortisone inhibits granulocyte-macrophage colony-stimulating factor production from normal human peripheral blood mononuclear cells and CD3+ T cells

Normal human peripheral blood mononuclear cells (MNCs), particularly T lymphocytes (T cells), are a rich source of granulocyte-macrophage colony-stimulating factor (GM-CSF). Glucocorticoids are known to inhibit GM-CSF production in in vitro cultures of a human fibroblast cell line and in normal human blood monocytes and alveolar macrophages. To determine whether glucocorticoids also inhibit GM-CSF production from normal human MNCs and T cells, we set up cultures of normal human MNCs and T cells in a liquid system in the presence and absence of 5, 50, and 250 microg/dL of hydrocortisone, and an hour later, a constant dose of 50-ng/mL Escherichia coli lipopolysaccharide (LPS) or 10-microg/mL phytohemagglutinin (PHA) was added. After three days, cell counts and GM-CSF levels were determined. Administering 50- and 250-microg/dL hydrocortisone decreased lymphocyte recovery from MNC cultures with LPS (p < or = 0.01), and 250 microg/dL of hydrocortisone decreased lymphocyte recovery from MNC and T-cell cultures with PHA (p < or = 0.03). The amount of GM-CSF produced from PHA-stimulated MNCs was about 100-fold higher than that produced from LPS-stimulated MNCs. The magnitude of GM-CSFs produced in MNC and T-cell cultures stimulated by PHA was comparable (p=0.88). Administering hydrocortisone at 5, 50, and 250 pg/dL decreased GM-CSF production (p < 0.003) in LPS- or PHA-stimulated MNC cultures and in PHA-stimulated T-cell cultures. PHA (not tested with LPS)-stimulated GM-CSF messenger RNA (mRNA) expression was blocked by hydrocortisone. These results indicate that lower concentrations of hydrocortisone inhibit GM-CSF production from normal human blood MNCs and T cells entirely by inhibiting the expression of GM-CSF mRNA, and higher concentrations of hydrocortisone inhibit by a combined effect of inhibiting the expression of GM-CSF mRNA and decreasing the lymphocyte count.     

Characterization of the microheterogeneities of PIXY321, a genetically engineered granulocyte-macrophage colony-stimulating factor/interleukin-3 fusion protein expressed in yeast

PIXY321, a human cytokine analog genetically engineered by the fusion of granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-3 (IL-3), was expressed in yeast under the control of the alcohol dehydrogenase 2 (ADH2) promoter and the alpha-mating factor expression system. To provide the material necessary for the evaluation of PIXY321 in clinical trials, the production was scaled up to the 1200-1 scale and the PIXY321 molecule isolated by four successive steps of ion-exchange chromatography. Multiple heterogeneities, due to the presence of different patterns of glycosylation as well as multiple amino acid sequences at both N and C termini, were characterized on the purified molecule using complementary analytical techniques including electrophoresis, liquid chromatography and electrospray mass spectrometry. Four different N-terminal sequences were identified but simplified to a reproducible ratio of two sequences, the mature form and a form starting at Ala3, by adjustment of the process conditions. Molecules lacking 1-6 residues at the C-terminus were identified and their relative frequencies quantified. Amino acid modifications, such as three oxidized Met residues at positions 79, 141 and 187 and one deamidated Asn residue at position 176, were detected at low level. Microheterogeneities in glycosylation were characterized on four different sites, one located in the GM-CSF portion and three in the IL-3 portion of the molecule. The sites were shown to be differentially occupied and to carry 0-10 mannose residues according to their location in the sequence. Precise measurement of the heterogeneities at the molecular level were used to tune the process conditions and ensure reproducibility of the clinical product between lots.     

Effect of granulocyte-macrophage colony-stimulating factor on leukocyte function in cirrhosis

Clinical outcomes of 95 second-trimester fetuses prospectively considered to have echogenic bowel at ultrasound were compared with a control group of 110 consecutive second-trimester fetuses. Among the 95 fetuses in the study group, 64 (67%) had moderately echogenic (grade 2) or markedly echogenic (grade 3) bowel relative to the liver. Among the 110 fetuses in the control group, only two (1.8%) had moderately echogenic (grade 2) bowel; the rest (98.2%) had isoechoic (grade 0) or midly echogenic (grade 1) bowel relative to the liver. Adverse outcomes occurred in 45 of the 95 fetuses (47%) with echogenic bowel compared with eight of the 110 fetuses (7.27%) in the control group (P < .01; relative risk, 6.5; 95% confidence interval, 3.2, 13.1). Adverse outcomes included chromosomal abnormalities, intrauterine growth retardation, fetal demise, or other fetal anomalies. Within the study group, adverse outcomes occurred in 40 of the 64 fetuses (62%) with grade 2 or 3 bowel echogenicity, compared with five of the 31 fetuses (16%) with grade 1 echogenicity. Echogenic bowel is associated with an increased risk of adverse fetal outcome and this risk is confined primarily to grades 2 and 3 echogenicity.     

Inhaled corticosteroids increase interleukin-10 but reduce macrophage inflammatory protein-1alpha, granulocyte-macrophage colony-stimulating factor, and interferon-gamma release from alveolar macrophages in asthma

In the present study, we examined denervation-induced changes in the sensitivity of hypothalamic postsynaptic serotonin1A (5-HT1A) receptor function with respect to changes in the dose-dependent elevation in plasma hormones [adrenocorticotropic hormone (ACTH), corticosterone, prolactin, oxytocin, prolactin, renin and vasopressin] by the 5-HT1A agonist 8-hydroxy-2-(dipropylamino)tetralin (8-OH-DPAT). Rats received intracerebroventricular (i.c.v.) injections of the serotonin neurotoxin 5,7-dihydroxytryptamine (5,7-DHT) or vehicle (0.1% ascorbate in saline) 3 weeks before challenge with increasing doses of 8-OH-DPAT (0, 10, 50 or 200 micrograms/kg s.c.). The effectiveness of 5,7-DHT-induced destruction of serotonergic neurons was confirmed by a 93% reduction in [3H]paroxetine-labeled 5-HT uptake sites in the hypothalamus. No changes in basal levels of ACTH, corticosterone, oxytocin, prolactin, renin and vasopressin were observed in rats that received i.c.v. 5,7-DHT injections. The dose-response curves for 8-OH-DPAT-induced elevations of plasma corticosterone and prolactin levels were shifted to the left in rats treated with 5,7-DHT, whereas no significant difference in the ACTH dose-response curve was observed between rats treated with vehicle and rats treated with 5,7-DHT. In contrast, the maximal oxytocin response to 8-OH-DPAT was attenuated in rats treated with 5,7-DHT. A 5,7-DHT-induced decline in the synthesis of oxytocin could explain this phenomenon. Although 8-OH-DPAT did not increase plasma levels of renin or vasopressin in rats treated with vehicle, 8-OH-DPAT produced an elevation (75%) in plasma renin concentration but not in vasopressin levels in rats that received i.c.v. injections of 5,7-DHT. No change was observed in [3H]8-OH-DPAT labeled 5-HT1A receptors in the hypothalamus. In summary, denervation of hypothalamic serotonergic nerve terminals produces supersensitivity of some neuroendocrine responses to 8-OH-DPAT independent of changes in the density of hypothalamic 5-HT1A receptors.     

Expression of granulocyte-macrophage colony-stimulating factor receptors in human prostate cancer

This investigation examined the effects of NaHCO3 loading on lactate concentration ([La]), acid-base balance, and performance for a 603. 5-m sprint task. Ten greyhounds completed a NaHCO3 (300 mg/kg body weight) and control trial in a crossover design. Results are expressed as means +/- SE. Presprint differences (P < 0.05) were found for NaHCO3 vs. control, respectively, for blood pH (7.47 +/- 0.01 vs. 7.42 +/- 0.01), HCO-3 (28.4 +/- 0.4 vs. 23.5 +/- 0.3 meq/l), and base excess (5.0 +/- 0.3 vs. 0.2 +/- 0.3 meq/l). Peak blood [La] increased (P < 0.05) in NaHCO3 vs. control (20.4 +/- 1.6 vs. 16.9 +/- 1.3 mM, respectively). Relative to control, NaHCO3 produced a greater (P < 0.05) reduction in blood base excess (-18.5 +/- 1.4 vs. -14.1 +/- 0.8 meq/l) and HCO-3 (-17.4 +/- 1.2 vs. -12.8 +/- 0.7 meq/l) from presprint to postexercise. Postexercise peak muscle H+ concentration ([H+]) was higher (P < 0.05) in NaHCO3 vs. control (158.8 +/- 8.8 vs. 137.0 +/- 5.3 nM, respectively). Muscle [H+] recovery half-time (7.2 +/- 1.6 vs. 11.3 +/- 1.6 min) and time to predose values (22.2 +/- 2.4 vs. 32.9 +/- 4.0 min) were reduced (P < 0.05) in NaHCO3 vs. control, respectively. No differences were found in blood [H+] or blood [La] recovery curves or performance times. NaHCO3 increased postexercise blood [La] but did not reduce the muscle or blood acid-base disturbance associated with a 603.5-m sprint or significantly affect performance.     

Cloning and characterization of the human interleukin-3 (IL-3)/IL-5/ granulocyte-macrophage colony-stimulating factor receptor betac gene: regulation by Ets family members

High-affinity receptors for interleukin-3 (IL-3), IL-5, and granulocyte-macrophage colony-stimulating factor (GM-CSF) are composed of two distinct subunits, a ligand-specific chain and a common beta chain (betac). Whereas the mouse has two homologous beta subunits (betac and betaIL-3), in humans, only a single beta chain is identified. We describe here the isolation and characterization of the gene encoding the human IL-3/IL-5/GM-CSF receptor beta subunit. The gene spans about 25 kb and is divided into 14 exons, a structure very similar to that of the murine betac/betaIL-3 genes. Surprisingly, we also found the remnants of a second betac chain gene directly downstream of betac. We identified a functional promoter that is active in the myeloid cell lines U937 and HL-60, but not in HeLa cells. The proximal promoter region, located from -103 to +33 bp, contains two GGAA consensus binding sites for members of the Ets family. Single mutation of those sites reduces promoter activity by 70% to 90%. The 5' element specifically binds PU.1, whereas the 3' element binds a yet-unidentified protein. These findings, together with the observation that cotransfection of PU.1 and other Ets family members enhances betac promoter activity in fibroblasts, reinforce the notion that GGAA elements play an important role in myeloid-specific gene regulation.