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L L Thomas

Publications and source records attributed to L L Thomas.

At least 37 records · Page 2Linked to original sources
PubMed1993

Eosinophil major basic protein enhances the expression of neutrophil CR3 and p150,95.

BACKGROUND: We examined the effect of major basic protein (MBP) stimulation on the expression of the neutrophil B2-integrins: LFA-1 (CD11a/CD18), CR3 (CD11b/CD18), and p150,95 (CD11c/CD18). METHODS: Incubation of neutrophils with 0.75 to 3.0 mumol/L MBP for 30 minutes at 37 degrees C resulted in concentration-dependent increases in CR3 expression as detected by staining with the CD11b-specific monoclonal antibody, Leu-15. RESULTS: The expression of CR3 was significantly (p < 0.001) higher when neutrophils were stimulated with 1.5 mumol/L (53% +/- 9% increase) or 3.0 mumol/L (100% +/- 17% increase) MBP as compared with unstimulated neutrophils. The kinetics of MBP-stimulated CR3 expression were rapid and were similar to those of 100 nmol/L. N-formyl-methionyl-leucyl-phenylalanine-stimulated enhancement of CR3 expression. Incubation of neutrophils with reduced and alkylated MBP resulted in significantly lower (p < 0.05) increases in CR3 expression as compared with stimulation with native MBP. In addition, neither eosinophil cationic protein nor eosinophil-derived neurotoxin altered neutrophil CR3 expression. MBP stimulated minimal increases in LFA-1 expression. However, staining with the monoclonal antibody Leu-M5 (anti-CD11c) revealed that MBP stimulated significant increases in the expression of p150,95. CONCLUSIONS: These results indicate that MBP stimulates the increased expression of neutrophil adhesion molecules, which in turn may enhance the inflammatory role of neutrophils in the late-phase events of allergic diseases.

Blood Proteins↗
PubMed1992

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.

Antigens, Differentiation, B-Lymphocyte↗
PubMed1992

Eosinophil granule proteins in peripheral blood granulocytes.

Eosinophils contain four principal cationic proteins, major basic protein (MBP), eosinophil-derived neurotoxin (EDN), eosinophil cationic protein (ECP), and eosinophil peroxidase (EPO). To determine the quantities of these proteins in granulocytes and whether they are specific to eosinophils, their concentrations in lysates of human granulocytes were measured using specific radioimmunoassays. The effect of different methods for eosinophil lysis on the recovery of the proteins was also studied. Maximal recovery occurred at pH 2 for MBP and pH 5.6 for the other granule proteins. The proteins cosedimented with eosinophils and their concentrations (mean +/- SEM) in ng/10(6) eosinophils (and in nM/10(6) eosinophils) were: MBP, 8,982 +/- 611 (641.6); EDN, 3,283 +/- 116 (178.4); ECP, 5,269 +/- 283 (250.9); and EPO, 12,174 +/- 859 (171.5). Basophils from a normal person contained (in ng/10(6) cells) MBP, 2,374; EDN, 214; ECP, 77; and EPO, 17. Highly purified neutrophils contained (in ng/10(6) cells) MBP, 3 +/- 0.5; EDN, 72 +/- 9; and ECP, 50 +/- 12. Therefore we conclude that these proteins are mainly expressed in eosinophils, but that certain ones are present in basophils and neutrophils.

Basophils↗
PubMed1992

Cellular uptake and degradation of phosphorothioate oligonucleotides by marine and freshwater ciliates.

To date, no antisense studies have been reported with either ciliated protozoa or marine organisms. This study examines the feasibility of using antisense oligonucleotides to alter gene expression in marine and freshwater ciliates. Radiolabeled, phosphorothioate-modified oligonucleotides were used to investigate whether ciliates take up and degrade oligonucleotides present in the culture medium. With all three ciliates examined, Euplotes crassus, Tetrahymena thermophila, and Oxytricha nova, the oligonucleotide in the culture medium was degraded very rapidly (> 90% in 8 h). The degradation probably occurred when the cells filtered the culture medium through the oral apparatus. Our results indicate that experiments involving the uptake of oligonucleotides from the culture medium are likely to be successful with ciliated protozoa. In studies designed to examine the uptake of fluorescent oligonucleotide by Euplotes cells, we found that dead or dying cells have a high affinity for fluorescein-labeled oligonucleotide. These results illustrate the importance of careful studies when only certain cell populations are found to have a high affinity for oligonucleotide. Although the seawater culture medium used to grow Euplotes causes some oligonucleotide to precipitate, this problem is not serious at concentrations > or = 1 microM oligonucleotide. Thus, it should be possible to use antisense oligonucleotides to manipulate gene expression in other marine organisms.

Animals↗
PubMed1992

Effectiveness of low dose cyclosporine in acquired aplastic anaemia with severe neutropenia.

Six patients with acquired aplastic anaemia were treated with cyclosporine (5 mg/kg/day) either alone or in combination with corticosteroids. A favourable response was observed in 4, including 2 patients presenting with an absolute granulocyte count of less than 0.2 x 10(9)/l. The 6th patient showed no effect after 6 wk of therapy and was thereafter successfully treated with anti-thymocyte globulin (ATG). Side effects of cyclosporine therapy were minimal (maximum follow-up 20 months). Temporary discontinuation of the drug in 1 patient resulted in a relapse which responded to reinstitution of therapy. Our results indicate that cyclosporine may be an effective, well-tolerated agent in acquired aplastic anaemia even in previously untreated patients with severe neutropenia.

Adult↗
PubMed1991

Treatment of azotemic, nonoliguric, anemic patients with human recombinant erythropoietin raises whole-blood viscosity proportional to hematocrit.

It has been reported that patients with azotemia have reduced red blood cell (RBC) deformability. Since this is a major determinant of whole-blood viscosity (WBV) and rigid RBCs increase WBV disproportionately relative to the level of hematocrit, it is conceivable that sustained improvement of hematocrit with recombinant human erythropoietin (rhEPO) therapy in azotemic patients might result in abnormally raised WBV. To address this concern, WBV and plasma viscosity (PV) were measured in 9 adult patients (4 men, 5 women) with anemia (mean hematocrit 29.2 +/- 2.7%) and azotemia [mean serum creatinine concentration 339.85 +/- 102.44 mumol/l (3.8 +/- 1.1 mg/dl)] before and after 6 months of treatment with rhEPO (50-175 U/kg given intravenously thrice weekly). Baseline and post-treatment hematocrit, WBV and PV were compared to values derived in 50 normal adult subjects with normal renal function [25 women, 25 men; mean serum creatinine concentration 79.56 +/- 8.84 mumol/l (0.9 +/- 0.1 mg/dl), mean hematocrit 42.4 +/- 3.7%]. To compare rheologic factors at subnormal hematocrits, blood from subjects with normal renal function was diluted with autologous plasma to achieve a range of hematocrits from 20 to 50%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Noncytotoxic activation of neutrophils by eosinophil granule major basic protein. Effect on superoxide anion generation and lysosomal enzyme release.

Eosinophil granule major basic protein (MBP) and neutrophils have each been implicated in the inflammatory late phase events of allergic disease. Based on this association and flow cytometric evidence presented in this report for MBP binding to neutrophils, we examined the ability of MBP to activate human neutrophils. Incubation of neutrophils with 0.5 to 3.0 microM MBP at room temperature produced a concentration-dependent chemiluminescence (CL) response that peaked after 50 to 70 min. Reduced-and-alkylated MBP, eosinophil cationic protein, and eosinophil-derived neurotoxin did not induce CL. MBP-induced CL was abrogated in the absence of Ca2+ and was absent in neutrophils isolated from two individuals with chronic granulomatous disease. MBP also stimulated release of superoxide anion (O2-) and lysozyme but not beta-glucuronidase or lactate dehydrogenase. Additionally, 1.5 microM MBP in combination with FMLP or platelet-activating factor stimulated a synergistic increase in O2- release from cytochalasin B-treated neutrophils. The degree of synergism with FMLP or platelet-activating factor was inversely related (p less than 0.005) to the level of MBP-induced O2- release. These results indicate that MBP activates neutrophils in a noncytolytic fashion and provide evidence that eosinophil-neutrophil collaboration may contribute to the pathogenesis observed in allergic late phase reactions.

Blood Proteins↗
PubMed1989

Human basophils selectively express the Fc gamma RII (CDw32) subtype of IgG receptor.

The role of IgG antibody in the sensitization of human basophils and mast cells to antigen is uncertain. To help resolve this uncertainty, we characterized by two-color fluorometric analysis the Fc receptors for IgG (Fc gamma R) on human basophils. Basophil-containing mononuclear cell fractions of atopic and nonatopic adult volunteers were incubated sequentially with fluorescein isothiocyanate-conjugated murine monoclonal IgE and biotinylated monoclonal antibodies (MAb) that bind specifically to the different Fc gamma R subtypes. Binding of biotinylated MAbs was visualized after subsequent incubation with phycoerythrin-strepavidin conjugate. Basophils did not react with a murine monomeric IgG2a, which binds specifically through its Fc to the high-affinity Fc gamma RI (CD64), or with MAbs specific for the low-affinity Fc gamma RIII (CD16). However, basophils reacted with a MAb specific for the low-affinity Fc gamma RII (CDw32). The profile of basophil Fc gamma R expression was not altered after brief IgE-mediated activation. In addition, pretreatment with gamma interferon, which induced expression of Fc gamma RI (CD64) on neutrophils, did not induce Fc gamma RI expression on basophils. These results indicate that the Fc gamma R present on basophils is exclusively of the Fc gamma RII (CDw32) subtype. The absence of the high-affinity Fc gamma RI (CD64) suggests that antigenic sensitization of basophils by monomeric IgG does not occur.

Antigens, CD↗
PubMed1989

Pharmacological control of human basophil histamine release stimulated by eosinophil granule major basic protein.

Eosinophil granule major basic protein (MBP) is a 13,800 MW arginine-rich polypeptide that is unique among basic molecules in its ability to stimulate human basophil histamine release. We examined the Ca2+ requirements and pharmacological regulation of MBP-stimulated histamine release. Minimal MBP-induced histamine release occurred in the absence of extracellular Ca2+, whereas addition of 0.1 mM Ca2+ resulted in 70% of the maximum histamine release response. Maximum histamine release required 0.5 to 1 mM extracellular Ca2+. The MBP-induced histamine release was blocked by a calmodulin antagonist and by theophylline and was partially inhibited by an inhibitor of phospholipase A2. Release was unaffected by inhibition of protein kinase C. Basophil pretreatment with pertussis toxin also resulted in a concentration-dependent inhibition of release, suggesting involvement of a GTP regulatory protein in the activation mechanism. Histamine release stimulated by a 13,900 MW poly-L-arginine exhibited a dissimilar pharmacological profile from that of MBP. These results support the non-cytolytic nature of the MBP activation mechanism and identify pharmacological approaches for control of MBP-induced mediator release.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1988

IgE-mediated sensitivity to Trichophyton rubrum in a patient with chronic dermatophytosis and Cushing's syndrome.

Persistent Trichophyton rubrum infection has been observed previously in association with Cushing's syndrome. In this article, we demonstrate IgE-mediated sensitivity to Trichophyton in a patient with chronic dermatophytosis secondary to Cushing's syndrome. Cell-mediated immunity was absent, but Trichophyton extract produced an immediate skin response and also stimulated a concentration-dependent histamine release from basophils of the patient. After adrenalectomy, cell-mediated immunity to Trichophyton was restored, and infection was confined to the nails. Skin and leukocyte sensitivity to Trichophyton extract persisted and was even more pronounced than the sensitivity before adrenalectomy. RAST measurement confirmed the presence of Trichophyton-specific IgE after adrenalectomy. These results provide further evidence that IgE-mediated inflammatory events may be initiated by Trichophyton infection.

Adult↗
PubMed1988

Ifosfamide and VP-16213 combination chemotherapy combined with ablative chemotherapy and autologous marrow transplantation as salvage treatment for malignant lymphoma.

Eighteen patients with high-grade malignant lymphoma were treated with ifosfamide-VP16213 combinations after failing to respond completely or after relapsing on CHOP-like therapy. Responders to the salvage therapy were subsequently treated with ablative chemotherapy (BCNU, VP-16213, Ara-C and melfalan) and autografted. Of these 18 patients six were in relapse, six were partial responders and six failed CHOP-like therapy. There were two complete remissions and seven partial responses to the ifosfamide-VP-16213 combinations. Of them, eight patients were transplanted, together with one non-responder. Four of these nine patients were disease-free survivors 18-34 months after autografting. There were two early deaths: one before and one during the autografting procedure. Using one of the best salvage therapy combinations followed by high-dose chemotherapy and autografting is feasible. The results in this pilot study suggest that an appreciable number of patients may be cured by this procedure.

Adolescent↗
PubMed1988

Social skills training in the rehabilitation of patients with traumatic closed head injury.

This research used a traditional social skills training program in the remediation of documented social behavior deficits of severely head-injured persons. More than two years after injury, four severely head-injured persons participated in a skills training program with five components: (1) instruction in the rationale for modifying target behaviors, (2) modeling the correct form of the behaviors, (3) behavioral rehearsal, (4) videotape feedback on performance, and (5) social reinforcement of correct behaviors. The research design was a multiple baseline across behaviors design with four replications. Three patients showed clear treatment effects with evidence of generalization across situations and maintenance of gains at follow-up one year later, thus supporting the applicability of social skills training to this cognitively impaired population.

Adult↗
PubMed1987

Methylxanthine bronchodilators potentiate multiple human neutrophil functions.

Methylxanthines, including the bronchodilators theophylline and aminophylline, in high concentrations (greater than 10(-4) M) inhibit cyclic nucleotide phosphodiesterase activity and in low, clinically relevant concentrations (10(-5) to 10(-4) M) are antagonists of extracellular adenosine receptors. The effect of therapeutic concentrations of methylxanthines on human neutrophil functions stimulated by N-formyl-methionyl-leucyl-phenylalanine (FMLP) was examined. Preincubation of cytochalasin B-treated neutrophils with 10(-5) M to 3 X 10(-3) M methylxanthine resulted in a biphasic, concentration-dependent effect on neutrophil aggregation, lysosomal enzyme release, and superoxide anion formation. At 10(-5) to 10(-4) M, theophylline and aminophylline potentiated neutrophil aggregation, lysosomal enzyme release (30 to 50%, p less than 0.005), and superoxide anion formation (30 to 60%, p less than 0.005). 1-Methyl-3-isobutylxanthine at these same concentrations potentiated only neutrophil aggregation and lysosomal enzyme release (30 to 40%, p less than 0.005). The three methylxanthines inhibited each response up to 90% at concentrations greater than 10(-4) M. 8-Phenyltheophylline, which does not inhibit phosphodiesterase activity, produced only potentiation. Preincubation of neutrophils with adenosine deaminase mimicked the methylxanthine potentiation, whereas addition of adenosine (3 X 10(-8) to 3 X 10(-7) M) reversed the methylxanthine-induced potentiation in a concentration-dependent manner. These results indicate that therapeutic concentrations of methylxanthines may potentiate neutrophil activation in vivo by competing with circulating adenosine for neutrophil adenosine receptors.

1-Methyl-3-isobutylxanthine↗