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H J Wedner

Publications and source records attributed to H J Wedner.

At least 55 records · Page 3Linked to original sources
PubMed1985

The role of glutathione in lymphocyte activation. I. Comparison of inhibitory effects of buthionine sulfoximine and 2-cyclohexene-1-one by nuclear size transformation.

The role of glutathione (GSH) in lectin-induced lymphocyte activation can be studied by quantitating lectin-induced nuclear size transformation in the presence of variable degrees of GSH depletion. Buthionine sulfoximine (BSO) inhibits intracellular GSH synthesis by inhibition of the enzyme gamma-glutamyl-cysteine synthetase. By combining endogenous GSH depletion in cell cultures with BSO-induced inhibition of GSH synthesis, lectin-induced lymphocyte activation can be studied at various concentrations of soluble intracellular GSH. With this approach, the percentage of lymphocytes undergoing a nuclear size transformation is minimally affected despite depletion of soluble intracellular GSH to 0.27 nmol/10(7) cells (PBL), which represents approximately 95% depletion of intracellular GSH. When soluble intracellular GSH is depleted to undetectable levels (less than 0.10 nmol/10(7) cells) there is a 10 to 12% reduction in the number of cell nuclei transformed. However, in all BSO-pretreated cultures the lectin-induced nuclear size transformation is intermediate between resting and blast-transformed lymphocytes, suggesting only partial (or aborted) activation. The partial activation response observed in BSO-pretreated cultures may be due to mobilization of the protein-bound pool of GSH, which is relatively resistant to depletion by BSO. That the inhibition of full blast transformation is truly due to GSH depletion was proven by experiments in which GSH was repleted exogenously and a full blast transformation was restored. The results of previous work in our laboratory had shown that the sulfhydryl-reactive agent 2-cyclohexene-1-one (2-CHX) was a potent inhibitor of activation at soluble intracellular GSH concentrations well above 0.27 nmol/10(7) PBL. In the present study, the dose-dependent inhibition of activation by 2-CHX was confirmed, but it was shown that the degree of inhibition caused by 2-CHX could be at least partially dissociated from the level of intracellular GSH present at the time of lectin addition and that the inhibitory potential of 2-CHX exceeded that of BSO at comparable levels of soluble intracellular GSH. Thus, the inhibitory properties of 2-CHX cannot be accounted for solely on the basis of GSH depletion.

Buthionine Sulfoximine↗
PubMed1984

The T lymphocyte antigen receptor. A critical review of recent experimental literature.

The search for the true nature of the T-cell receptor for antigen has been impeded by several factors including: (1) the relatively low density of antigen binding receptors on T cells: (2) the lack of large quantities of homogeneous T cells for analysis; (3) the inability to study the T receptor protein independent of the T-cell surface; (4) the greater degree of complexity of the receptor compared to conventional immunoglobulin, and (5) possibly the relatively low binding affinity of the receptor for free antigen. Despite these impediments extensive immunobiological evidence has accumulated that the T receptor possesses idiotypic determinants analogous to those of conventional immunoglobulins on the B-cell surface. When both T and B cells recognize the same antigenic determinant they share a common idiotypic determinant. Nonetheless, recent evidence from methods examining gene expression in T cells speaks against VH gene expression. Thus, it appears that two entirely different gene pools, and possibly different mechanisms, have evolved in B and T cells to generate the equally vast diversity of immunoglobulins and T-antigen-receptor molecules. MHC products play a central role in T-cell receptor function by governing intercellular interactions through MHC restriction. MHC restriction is a property acquired by T cells during intrathymic maturation. The function (if any) of MHC products on the T-cell surface remains unknown, although much evidence suggests that the T receptor must be able to recognize MHC products in association with antigen on antigen-presenting cells. The altered-self theory seems to best explain the constraints governing the T receptor's recognition of antigen plus MHC product on the antigen-presenting cell. The differentiation antigens on the T-cell surface defined by monoclonal antibodies have proven extremely useful as markers of functionally distinct T-cell subsets. More recently a function role for three of these antigens, T3, T4, and T8 has been discovered. The T3 antigen now appears to be intricately associated with the antigen-specific (or clonotypic) T-receptor molecule so as to promote antigen recognition. In addition, low concentrations of anti-T3 are mitogenic for T cells suggesting another possible function for the T3 molecule. The T8 and T4 molecules seem to recognize class I and class II MHC determinants, respectively, in a manner which governs cytotoxicity toward cells expressing these MHC determinants. The advent of T-cell clones and T-cell hybridomas has overcome many of the impediments toward the search for the T receptor.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1983

Glutathione depletion inhibits amylase release in guinea pig pancreatic acini.

Isolated guinea pig pancreatic acini were specifically depleted of glutathione by treatment with 2-cyclohexene-1-one (2-CHX-1). Untreated acini contained 4.3 +/- 0.6 micrograms of glutathione per milligram protein. Incubation with 1 mM 2-CHX-1 for 5 min at 37 degrees C depleted glutathione to 17% of control values; 5 mM 2-CHX-1 depleted glutathione to less than 4% of control values. Incubation with 2-CHX-1 also impaired the ability of the isolated acini to secrete amylase in response to stimulation with carbachol and the ionophore A23187. The depletion of glutathione and the inhibition of amylase secretion by 2-CHX-1 were both dose dependent and time dependent. Incubation of acini with 2 mM 2-CHX-1 for 15 min at 37 degrees C reduced glutathione levels to 6.6% of control and reduced carbachol-stimulated amylase release to 63% of control. Higher doses of 2-CHX-1 or longer incubations resulted in greater depletion of glutathione and greater inhibition of carbachol-induced amylase release. These data indicate that specific depletion of glutathione impairs the ability of isolated acini to secrete amylase in response to physiological and pharmacologic stimuli and suggest that glutathione has a role in stimulus-secretion coupling in the exocrine pancreas.

Amylases↗
PubMed1983

Aspirin desensitization in aspirin-sensitive asthma: failure to maintain a desensitized state during prolonged therapy.

A patient with a history of asthma induced by acetylsalicylic acid (ASA) was found to be ASA sensitive when orally challenged with ASA. She was successfully desensitized using incremental doses of ASA given orally and maintained on ASA or other nonsteroidal antiinflammatory (NSAI) agents for the treatment of arthritis. After 6 months of uninterrupted therapy the patient developed asthmatic symptoms that were related to ASA and NSAI drug therapy. Although desensitization may be achieved in patients with ASA-sensitive asthma, sensitivity may recur despite continuous therapy.

Adult↗
PubMed1983

Cutaneous anergy and marrow suppression as complications of gastroplasty for morbid obesity.

Although serious morbidity from gastric restriction for morbid obesity is rare, outflow tract dilation after gastroplasty has become a well-recognized complication, and reoperation to decrease outflow tract size has become increasingly common. We report the case of a patient who developed outflow tract obstruction with subsequent malnutrition, recurrent infections, and marrow suppression. Extensive immunologic evaluation revealed impaired cutaneous reactivity to a battery of recall antigens. Other in vitro T cell functions, B cell functions, neutrophil respiration, and quantification of complements were within normal limits. The patient's immunodeficiency was attributed to protein-calorie malnutrition and was corrected with total parenteral nutrition. Recovery of immune function with renutriture was demonstrated, and coincident resolution of infection and marrow suppression also occurred. Because of the reversibility of the immunologic abnormality with appropriate nutritional therapy, it is important to consider and treat malnourishment in connection with any operation in which oral intake is severely limited.

Adult↗
PubMed1982

Desensitization of patients allergic to penicillin using orally administered beta-lactam antibiotics.

When patients allergic to penicillin develop life-endangering infections that require treatment with beta-lactam antibiotics, they face a fatal infection or the possibility of a fatal allergic reaction. We have approached this situation by using an oral desensitization procedure before full-dose antibiotic therapy. Thirty consecutive patients with histories of allergic reactions to penicillin, positive immediate wheal and flare skin-test reactions to penicillin determinants, and life-threatening infections were studied. Bacterial endocarditis requiring penicillin G therapy led to desensitization of 19 patients, Pseudomonas sepsis of pneumonia requiring treatment led to desensitization of nine subjects, and staphylococcal infections requiring therapy with a penicillinase-resistant penicillin led to desensitization of two patients. Penicillin G or carbenicillin were administered orally, beginning with 100 U or 60 microgram, respectively. At 15-min intervals, progressively doubled doses were given during continuous monitoring for the appearance of allergic reactions. Within 5 hr, full therapeutic doses were administered intravenously. Skin-test reactions disappeared or diminished in all 23 subjects who were retested after desensitization. Full courses of antibiotic therapy and cure of the infections were accomplished in 30 of 30 patients. No deaths, anaphylaxis, or severe acute allergic reactions occurred. Pruritic cutaneous eruptions appeared in nine patients (30%) 6 to 48 hr after the onset of therapy. One patient developed reversible nephritis 3 wk into therapy with penicillin G. The results of this study suggest that oral desensitization is an effective, relatively safe approach to administering beta-lactam antibiotics to penicillin-allergic patients with life-threatening infections.

Administration, Oral↗
PubMed1981

Skin testing to detect penicillin allergy.

Skin testing for penicillin allergy with penicillin G (Pen G), penicilloic acid (PA), and penicilloyl poly-L-lysine (PPL) was performed on 740 subjects, and the results were assessed from epidemiologic and immunologic perspectives. Approximately 95% of these patients had histories of apparent allergic reactions to beta-lactam antibiotics, and 63% were skin-test positive. The prevalence of positive skin tests was related to the time that had elapsed between clinical reactions and skin testing. Ninety-three percent were skin-test positive 7 to 12 mo after reactions, and 22% were positive 10 yr or more after reactions. Patients under 30 yr of age had a prevalence of positive skin tests 1.7-fold higher than older patients. Testing with PPL, PA, and Pen G detected 76.3%, 55.3%, and 57.1% of the positive patients, respectively. Omission of PPL, PA, or Pen G would have led to a failure to detect 25.6%, 7.2%, and 6.2% of the positive patients, respectively. Subjects with skin tests positive to penicillin often reacted to skin tests with other beta-lactam antibiotics; 73% (41 of 56) reacted to ampicillin and 51% (38 of 74) reacted to cephalothin. No serious allergic reactions were provoked by testing. None of the 83 skin test--negative patients treated with beta-lactam antibiotics immediately after testing experienced acute allergic reactions. Two patients developed mild urticaria beginning 3 and 5 days into therapy. One skin test--negative patient experienced urticaria 3 hr after receiving oral penicillin 6 mo after skin testing. This patient's skin-test status immediately before therapy was unknown. These results support the position that testing with PPL, PA, and Pen G is a rapid, safe, and effective method for identifying patients at risk, or not at risk, for allergic reactions to penicillin.

Adolescent↗
PubMed1981

Inhibition of human polymorphonuclear leukocyte function by 2-cyclohexene-1-one. A role for glutathione in cell activation.

2-cyclohexene-1-one and diethyl maleate specifically decrease reduced glutathione (GSH) levels in human polymorphonuclear leukocytes (PMN) by direct conjugation, and by interaction with the glutathione-s-transferase system. Using these two nontoxic reagents we have examined the effect of decreased GSH levels on five parameters of PMN activation: superoxide generation, release of the lysosomal enzymes lysozyme and beta-glucuronidase, and increases in the influx of Na+ and Ca2+. When PMN pretreated with 2-cyclohexene-1-one or diethyl maleate were incubated with formyl-methionyl-leucyl-phenylalanine (FMLP) or the proteolytic fragment of the fifth component membrane of complement, C5a, agents that interact with surface membrane receptors, increases in all five parameters were inhibited in a dose-dependent manner. For O-2 generation and lysosomal enzyme release the ID50 for 2-CHX-1 was 40--90 micrometers corresponding with a 30--50% decrease in intracellular GHS. In contrast stimulation of treated PMN by the divalent cation ionophore A23187 or 5-hydroxyeicosatetraenoic acid was much less sensitive to depressed GSH; the ID50 for 2-cyclohexene-1-one was 1 mM or greater, corresponding with an 80--90% decrease in GSH. The effect of lowered GSH was not the result of decreased binding of FMLP to surface receptors because [3H]-FMLP binding studies demonstrated a two- to three-fold increase in the number of available binding sites. These data indicate that normal GSH levels are necessary for the transduction of the activation signal from the exterior to the interior of the PMN, but once initiated the activation sequence proceeds normally despite markedly lowered intracellular GSH.

Calcium↗
PubMed1981

Inhibition of lectin-induced lymphocyte activation by 2-cyclohexene-1-one: decreased intracellular glutathione inhibits an early event in the activation sequence.

The importance of normal intracellular glutathione (GSH) levels in the activation of human peripheral blood lymphocytes (PBL) by mitogenic lectins was explored using 2-cyclohexene-1-one (2-CHX-1), an agent that selectively decreases the levels of intracellular GSH. PBL incubated with mitogenic lectins and graded doses of 2-CHX-1 showed a dose-dependent inhibition of activation assayed by [3H]-thymidine uptake and percentage of blast transformation. 2.5 x 10(-5) M 2-CHX-1, a concentration that decreases GSH levels to less than 20% of control, caused an 80 to 90% suppression of both [3H]-thymidine uptake and blast transformation; lower concentrations were less effective. Time course studies showed that 2-CHX-1 was maximally effective only if added during the first 4 hr of culture. At the concentrations used, 2-CHX-1 was not cytotoxic to lectin-stimulated or unstimulated PBL and did not interfere with mitogen-lymphocyte interaction. These results suggest that adequate levels of glutathione are necessary for lymphocyte activation and that the glutathione requirement is exerted in the early activation sequence.

Cyclohexanes↗
PubMed1980

The effect of diamide on cyclic AMP levels and cyclic nucleotide phosphodiesterase in human peripheral blood lymphocytes.

The effect of diamide (diazene dicarboxylic acid bis[N,N'-dimethylamide) on cyclic AMP levels and cyclic nucleotide phosphodiesterase in human peripheral blood lymphocytes was examined. In the absence of mitogenic lectins, 5 . 10(-3)-1 . 10(-4) M diamide markedly increased intracellular cyclic AMP with variable effects at higher levels. In the presence of phytohemagglutinin or concanavalin A, 5 . 10(-4) M or higher diamide concentrations consistently decreased cyclic AMP levels, usually to control levels or below, while 1 . 10(-4)-1 . 10(-5) M diamide augmented the lectin-induced rise in cyclic AMP. When intact lymphocytes were incubated with diamide, phosphodiesterase activity against both cyclic AMP and cyclic GMP, assayed in homogenates of these cells, was inhibited at concentrations as low as 1 . 10(-6) M. In contrast, when diamide was incubated with phosphodiesterase extracted from lymphocytes there was a dual effect. At low substrate concentrations and high diamide concentrations diamide was a non-competitive inhibitor of phosphodiesterase with a Ki of 1.3--2.5 mM for cyclic AMP and 3.3--10 mM for cyclic GMP. In contrast, at high substrate concentrations diamide was an 'uncompetitive' activator of phosphodiesterase activity for both cyclic AMP and cyclic GMP. The effects of diamide could be largely or completely blocked by glutathione or dithiothreitol, indicating that sulfhydryl reactivity was involved in diamide's action on lymphocyte phosphodiesterase activity and intracellular cyclic AMP levels. These data demonstrate that diamide is a phosphodiesterase inhibitor both on phosphodiesterase extracted from lymphocytes and when incubated with intact lymphocytes and that diamide may increase or decrease intracellular cyclic AMP levels depending on the concentration of diamide used.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1980

Relationship of biosynthesis of slow reacting substance to intracellular glutathione concentrations.

To further elucidate the role of glutathione (GSH) in the biosynthesis of slow reacting substance (SRS), SRS generation was studied in rat basophilic leukemia cells that had been preincubated with 2-cyclohexen-1-one or diethyl maleate to decrease their intracellular GSH concentrations. At low GSH levels SRS formation was markedly inhibited. The formation of other lipoxygenase products was much less affected, although some decrease in 5-hydroxyicosatetraenoic acid formation also occurred, apparently due in part to less rapid reduction of the 5-hydroperoxide.

Animals↗
PubMed1980

Cyclic AMP concentrations in human peripheral blood lymphocytes. Changes in association with cell purification.

In studies over a several year period of cAMP in human peripheral blood lymphocytes, a wide range of concentrations has been from low values (1 to 5 pmole/10(7) cells) to high values (80 to 160). Evaluation of this variation indicated that between cell separation and completion of the experiment, there eas a progressive decrease in lymphocyte cAMP as determined by RIA or immunocytochemistry. After a 2 hr incubation at 37 degrees C, a new steady state was reached at 5% to 30% of the initial concentration. This phenomenon was unique to lymphocytes and not preventable by manipulation of the incubation conditions. The cause of the cAMP reduction was shown to be decreasing AC activity. These data suggested the possibility that AC was activated during cell isolation. However, the phenomenon was present in cells not exposed to dextran or Ficoll-Hypaque, and simulation of conditions employed during purification did not result in increased cAMP. Consequently, high-lymphocyte cAMP concentrations may be the normal levels in vivo.

Adenylyl Cyclases↗