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S Krilis

Publications and source records attributed to S Krilis.

At least 19 recordsLinked to original sources
PubMed2003

Cardiac disease in the antiphospholipid syndrome: recommendations for treatment. Committee consensus report.

The Committee reviewed cardiac involvement in the antiphospholipid antibody syndrome. The Committee's recommendations are: Valve abnormalities: anticoagulation is recommended for symptomatic patients with valvulopathy. Prophylactic antiplatelet therapy may be appropriate for asymptomatic patients (recommended by 13/17 experts in an independent review). Committee members disagreed whether corticosteroid therapy is helpful, but agree that distinguishing among presumptive valvulitis (valve thickening on echocardiogram), valve deformity and vegetations is important, as treatment implications may differ. Occlusive arterial disease (angina, myocardial infarction): the Committee recommends aggressive treatment of all risk factors for atherosclerosis (hypertension, hypercholesterolaemia, smoking) and liberal use of folic acid, B vitamins and cholesterol-lowering drugs (preferably statins). Hydroxychloroquine for cardiac protection in APS patients may be considered. The Committee also recommends warfarin anticoagulation for those who have suffered thrombosis in the absence of atherosclerosis, but recognizes that developing data may support the use of antiplatelet agents instead. Intracardiac thrombi: the Committee recommends intensive warfarin anticoagulation, and consultation with cardiac surgeons when appropriate. Ventricular dysfunction: the Committee has no recommendations on this aspect of cardiac disease. Pulmonary hypertension: the Committee recommends intensive anticoagulation with warfarin and clinical trials of bosentan, epoprostenol and other new agents.

Anticoagulants↗
PubMed1998

Antibodies to beta 2-glycoprotein-I: urea resistance, binding specificity, and association with thrombosis.

The aim of the present study was to evaluate the urea resistance and binding characteristics of anti-beta 2-glycoprotein I (anti-beta 2GPI) antibodies using standard anticardiolipin (aCL) and anti-beta 2GPI enzyme immunosorbent assays (ELISAs). Sera from patients with antiphospholipid syndrome (APS) (n = 22) and non-APS (n = 24), positive in a standard aCL ELISA, were tested in an anti-beta 2GPI ELISA performed in polystyrene-irradiated ELISA plates. Urea resistance aCL and anti-beta 2GPI ELISAs were performed by measuring the ability of antibodies to recognize antigen in the presence of 2 M urea. The serum dilution after urea treatment (D) expressed as a percentage of the serum dilution without urea treatment (D(o)) corresponding to the same optical density was defined as residual activity (RA = 100 D/D(o)). The higher the RA, the higher the resistance of the antibodies to urea. APS compared to non-APS sera had higher aCL binding (absorbance values ranging between 0.180 and 1.400; median, 0.717 vs 0.120-1.273; median, 0.250, respectively; P < 0.004). Six APS patients' sera had low aCL levels but they expressed RA > or = 30%. Anti-beta 2GPI antibodies were detected in 15 of 22 APS vs 3 of 24 non-APS patients (P < 0.03); RA > or = 30% was detected in 15 of 22 APS vs 1 of 23 non-APS patients (P < 0.004). Using a CL affinity column, antibodies were purified from three APS anti-beta 2GPI negative and three non-APS anti-beta 2GPI-positive patients and tested in a aCL ELISA, using highly purified bovine serum albumin (BSA) as a blocking agent (modified ELISA); reactivity was not detected in two APS and one non-APS sera. On the contrary, the reactivity of the purified antibodies was high when beta 2GPI was incubated with CL in the ELISA plates; thus some anti-beta 2GPI negative sera from APS patients recognized the CL/beta 2GPI complex, rather than CL or beta 2GPI alone. In conclusion, anti-beta 2GPI antibodies are common in the APS patients, but a number of such patients recognize the CL/beta 2GPI complex and not CL or beta 2GPI. Antibodies to either beta 2GPI or the CL/beta 2GPI complex derived from APS sera present a high resistance to urea. Anti-beta 2GPI antibodies of low urea resistance exist in a minority of non-APS patients with autoimmune disease.

Antibodies, Antiphospholipid↗
PubMed1994

The fifth domain of beta 2-glycoprotein I contains a phospholipid binding site (Cys281-Cys288) and a region recognized by anticardiolipin antibodies.

We have identified a phospholipid binding site in the fifth domain of beta 2-glycoprotein I (beta 2-GPI). Using synthetic peptides spanning the fifth domain of beta 2-GPI, we have shown that the presence of the sequence Glu274-Cys288 caused a decrease in the binding of purified anticardiolipin (aCL) antibodies in a modified cardiolipin (CL)-ELISA by inhibiting the binding of beta 2-GPI to CL. This peptide bound to and could be eluted from a CL affinity column in a manner similar to native beta 2-GPI. Peptides corresponding to other regions of the fifth domain had no inhibitory effect. The inhibitory activity was restricted to the sequence Cys281-Lys-Asn-Lys-Glu-Lys-Lys-Cys288. Peptides in which the two flanking cysteine residues were deleted or substituted with serine residues possessed no inhibitory activity, indicating that the conformation of this highly positively charged sequence may be critical for phospholipid binding. aCL antibodies purified from patients with autoimmune disease were shown to bind directly to wells coated with native beta 2-GPI but not to wells coated with a preparation of beta 2-GPI cleaved between Lys317 and Thr318. The integrity of this sequence is therefore critical for these antibodies to recognize beta 2-GPI, and the putative epitope for aCL antibodies is most likely to be in this region.

Amino Acid Sequence↗
PubMed1993

Expression of human recombinant beta 2-glycoprotein I with anticardiolipin antibody cofactor activity.

To enable the synthesis of beta 2-glycoprotein I mutants we have established a stable Chinese hamster ovary cell line that expresses human beta 2-glycoprotein I up to 2.9 micrograms/10(6) cells/day. Recombinant beta 2-glycoprotein I is identical to the purified native protein with respect to cofactor activity revealed in a modified anti-cardiolipin ELISA. Autoimmune type anti-cardiolipin antibody requires recombinant beta 2-glycoprotein I in a dose-dependent manner to bind cardiolipin whilst binding of infectious type antibody is inhibited. The purified recombinant beta 2-glycoprotein I in serum free medium exists as two oligosaccharide species which upon deglycosylation have identical apparent molecular weight to the deglycosylated native protein.

Animals↗
PubMed1993

Immortalization and characterization of human cell lines with mast cell and monocytic properties.

We have previously derived a cell strain which had both mast cell and monocytic properties from the bone marrow of a child with diffuse cutaneous mastocytosis. This cell strain, termed HBM-M, consisted of two cell populations both of which possessed certain ultrastructural, cytochemical and surface phenotypic features of degranulated mast cells. The cells also displayed cytochemical and surface phenotypic features of monocytes. These cells may represent a common bone marrow derived mast cell/monocyte precursor. Studies of human mast cells have been hindered by the fact that it is difficult to establish such cells in long-term culture. Thus, we sought to immortalize HBM-M cells by introducing Simian virus 40 large T-antigen. Following transfection by the strontium phosphate technique, transformed cells were selected, expanded and passaged until the cells entered a non-proliferative phase termed crisis. Certain clones passed through crisis 3 months later and by this means two immortal cell lines, HBM-MI-1 and HBM-MI-2, were obtained. The criterion for immortality was growth for greater than 100 population doublings. The immortal cell lines retained some, but not all, of the mast cell and monocytic properties of the original HBM-M cell strain. The immortalization of the cell strain HBM-M provides an opportunity to investigate the mast cell and monocytic properties of these cells, and the apparent relationship between mast cells and monocytes.

Animals↗
PubMed1990

Lipoxin A4 inhibits phosphoinositide hydrolysis in human neutrophils.

Lipoxins (LX) are trihydroxytetraene metabolites derived from arachidonic acid via an interaction between the 5- and 15-lipoxygenases. Preincubation of [3H] myo-inositol labeled PMN with 10-7M and 10-5M LXA4 for 1 minute at 37 degrees C resulted in a concentration dependent inhibition of the generation of [3H] IP3 and [3H] IP in cells subsequently stimulated by increasing doses of LTB4 or FMLP for 1 minute at 37 degrees C. Preincubation of PMN with LXA4 did not inhibit specific binding of [3H] LTB4 to PMN. These results indicate that LXA4 inhibits chemotactic factor-induced phosphoinositide hydrolysis at a post-receptor level.

Dose-Response Relationship, Drug↗
PubMed1990

Human tumour necrosis factor-alpha (TNF-alpha) directly stimulates arachidonic acid release in human neutrophils.

The ability of tumour necrosis factor-alpha (TNF-alpha) to directly stimulate phospholipid turnover from human neutrophils was studied. Stimulation with recombinant human (rH) TNF-alpha induced the release of significant amounts of radioactivity from [3H]arachidonic acid-labelled neutrophils. This stimulation was equipotent to that induced by the bacterial tripeptide formyl-methionyl-leucylphenylalanine (FMLP). The time of maximum stimulated release varied between donors, with the most common maximal stimulation being 45 min. Dose-response experiments indicated that 100-1000 U/ml rH TNF-alpha were required for the maximum stimulatory effect. High-performance liquid chromatography analysis of the supernatants revealed that the radioactivity was associated with arachidonic acid, but not with its metabolites, indicating that TNF-alpha stimulates the release of arachidonic acid from cellular phospholipids but does not stimulate its metabolism. A comparison of TNF-alpha with other cytokines indicated that stimulation of arachidonic acid release paralleled the 'priming' of neutrophils for enhanced superoxide production, raising the possibility that phospholipid turnover and priming of neutrophils are causally related.

Arachidonic Acids↗
PubMed1985

Purification of two allergens from Dermatophagoides pteronyssinus using monoclonal antibodies.

Fractionation of soluble extracts from the house dust mite Dermatophagoides pteronyssinus (DP) by SDS-PAGE and crossed immunoelectrophoresis (CIE) revealed at least fifty distinct protein components. Western blotting and crossed radioimmunoelectrophoresis (CRIE) indicated that fewer than one quarter of these components were allergens as determined by their ability to bind IgE from allergic individuals. Following immunization with a crude extract, two monoclonal antibodies were raised against distinct components which exhibited IgE binding capacities in Western blot and CRIE. Affinity chromatography using these monoclonal antibodies yielded components which elicited positive skin test reactions in patients allergic to DP.

Allergens↗
PubMed1985

Analysis of allergen-specific IgE responses in 341 allergic patients. Associations between allergens and between allergen groups and clinical diagnoses.

An allergic population of 341 patients was studied using 14 different allergen extracts in skin prick tests and radioallergosorbent tests (RAST) in an attempt to identify important allergen sources in the Sydney area and to examine relationships between these diagnostic methods and a number of clinical parameters. A computer based statistical analysis of the data revealed that: (a) male patients showed a significantly higher frequency of skin test reactivity to extracts of house dust and the house dust mite Dermatophagoides farinae; (b) the incidence of positive prick test reactions declined with age; (c) cross-reactive allergenic determinants were found in taxonomically-related extracts (e.g. between different house dust mites, pollens, and fungi); (d) a clear correlation emerged between relative potency using a histamine standard and RAST score which supports the continued use of histamine as a standard in skin prick testing; and (e) important associations between certain allergens and clinical diagnosis emerged (e.g. positive skin test reactions to house dust mites and epithelia but not pollens were associated with asthma).

Adolescent↗
PubMed1984

Antigens and allergens from the common house dust mite Dermatophagoides pteronyssinus. Part I. Demonstration of multiple allergens by immunochemical and biologic analyses.

The complexity of a highly allergenic water-soluble extract of the common house dust mite Dermatophagoides pteronyssinus has been investigated by use of the preparative fractionation techniques of ultrafiltration, gel permeation chromatography, and isoelectric focusing, and the allergenic properties of the resultant fractions are assessed by skin prick tests, RAST, and a histamine-release assay. In addition, two analytical approaches were used to identify allergens-radioimmunoelectrophoresis and a new technique for detecting IgE-binding proteins separated by isoelectric focusing and transferred onto a nitrocellulose membrane by transverse electrophoresis. These various techniques for allergen detection revealed differences in the number and distribution of allergens in the crude mite extract. The data obtained are consistent with the conclusion that allergenic activity of D. pteronyssinus extracts is due to the existence of a number of antigenically distinct allergens and not due to a single, major allergen.

Allergens↗
PubMed1984

Antigens and allergens from the common house dust mite Dermatophagoides pteronyssinus. Part II. Identification of the major IgE-binding antigens by crossed radioimmunoelectrophoresis.

Crossed immunoelectrophoresis demonstrated 51 antigens in a water-soluble extract of the house dust mite Dermatophagoides pteronyssinus. Autoradiography demonstrated that 11 of the antigens bound IgE antibodies in the sera of house dust mite-allergic patients. IgE antibodies in 23 different sera reacted with from one to eight antigens. On the basis of Lowenstein's (1978) definition of a "major allergen," two of the antigens, numbers one and 36 would be described as "major allergens." Apart from antigen number 36 that has already been demonstrated to be an important allergen in patients allergic to D. pteronyssinus, the clinical importance of the other 10 IgE-binding antigens has yet to be assessed. Reasons against use of the term "major allergen" and its replacement with the title "clinically important allergen" are advanced.

Allergens↗
PubMed1984

Specific binding of leukotriene C4 to ileal segments and subcellular fractions of ileal smooth muscle cells.

A specific high-affinity receptor for leukotriene C4 (LTC4) has been identified on segments of longitudinal smooth muscle from guinea pig ileum, in disrupted cells obtained from the ileal segments, and in subcellular fractions enriched for mitochondrial membranes and plasma membranes, respectively. Specific [3H]LTC4 binding at a fixed input at 4 degrees C reached a plateau at 60 min with each of the four preparations and was greater than 80% reversible after binding reached equilibrium by the introduction of excess unlabeled homoligand. LIGAND analysis demonstrated a single high-affinity receptor on the smooth muscle segments, the disrupted cells, and the subcellular fractions enriched for mitochondrial membranes and for plasma membranes with respective Kd values of 7.6 nM, 1.3 nM, 13 nM, and 8.5 nM. These Kd values overlap with the concentration of LTC4 known to elicit a spasmogenic response in the ileal muscle, indicating that the radioligand recognizes a receptor that mediates the biological response. Competition analysis with disrupted ileal cells and subcellular fractions with a fixed input of LTC4 radioligand and incremental concentrations of the natural sulfidopeptide leukotrienes demonstrated leukotriene D4 (LTD4) to be 1-3 logarithms less active than LTC4 and leukotriene E4 (LTE4) to be essentially inactive. Thus, ileal longitudinal smooth muscle cells possess a high-affinity receptor that is selective for LTC4 and that receptor exhibits both a plasma membrane and subcellular distribution.

Animals↗
PubMed1984

An analysis of the relationship between 5-lipoxygenase product generation and the secretion of preformed mediators from mouse bone marrow-derived mast cells.

The quantitative relationships between the secretion of a granule-associated mediator, beta-hexosaminidase, and the oxidative metabolism of arachidonic acid by the 5-lipoxygenase pathway were analyzed for a homogeneous population of T cell-dependent, bone marrow-derived, murine mast cells. The mast cells were either sensitized with a monoclonal IgE and challenged with specific antigen, or to bypass a transmembrane signal, were stimulated with calcium ionophore A23187. The released products of the 5-lipoxygenase pathway were quantitated by integrated ultraviolet absorbance after resolution by reverse phase-high performance liquid chromatography in the case of 5-hydroxy-eicosatetraenoic acid (5-HETE), and by separate radioimmunoassays for leukotriene C4 (LTC4) and leukotriene B4 (LTB4). The activation-release response of the cells was perturbated by the introduction of three pharmacologic agents, each directed to different steps in the 5-lipoxygenase pathway of arachidonic acid metabolism, and the action of each agent was determined for separate cell samples while present and after its removal by washing. 5,6-Dehydroarachidonic acid (5,6-DHA), an irreversible inhibitor of 5-lipoxygenase, prevented formation of 5-HETE from exogenous [14C]arachidonic acid and from membrane-derived arachidonic acid in a dose-related fashion when sensitized mast cells, preincubated with drug, were washed before antigen activation. Release of 5-HETE, LTC4, and LTB4 was inhibited by 5,6-DHA in a corresponding dose-related fashion, with a minimal preincubation period of 1 to 5 min before the cells were washed and subjected to antigen-dependent activation. In contrast, the inhibitory effect of 5,6-DHA on beta-hexosaminidase release was lost after three washes and was not evident after one wash unless the preincubation period was extended to 15 min. The capacity of 5,6-DHA to prevent leukotriene generation without altering beta-hexosaminidase release was also observed with ionophore-activated mast cells. Preincubation of sensitized cells with diethylcarbamazine (DEC), followed by a wash before antigen-dependent activation, produced inhibition of leukotriene generation, no effect on beta-hexosaminidase release, and augmentation of 5-HETE release at the maximum dose studied; thus, DEC interrupts the pathway distal to the formation of 5-hydroperoxy-eicosatetraenoic acid (5-HPETE) from arachidonic acid by 5-lipoxygenase. Preincubation of sensitized cells with incremental amounts of the prostacyclin analog U-60,257, followed by washing and antigen challenge, inhibited LTC4 release without altering the release of LTB4 or beta-hexosaminidase.(ABSTRACT TRUNCATED AT 400 WORDS)

8,11,14-Eicosatrienoic Acid↗
PubMed1983

Standardization of antigen E in ragweed pollen extracts using a monoclonal antibody-based enzyme immunoassay.

A hybridoma-derived monoclonal IgG antibody specific for ragweed AgE was used to develop a competitive binding enzyme immunoassay suitable for quantitation of antigen E levels in ragweed pollen extracts. The assay was capable of detecting as little as 30 ng/ml AgE in crude pollen extracts. The monoclonal antibody was shown to react with AgE present in commercial pooled pollen extracts from a number of ragweed species as well as a laboratory extract from a single species. In contrast to previous conventional xenoantisera, it could distinguish true ragweed (Ambrosia sp) from false ragweed (Franseria sp). The use of monoclonal antibodies in assay systems such as this offers a reproducible and widely applicable method for allergen standardization.

Allergens↗
PubMed1983

Bioconversion of C-6 sulfidopeptide leukotrienes by the responding guinea pig ileum determines the time course of its contraction.

The naturally occurring sulfidopeptide leukotrienes, leukotriene (LT) C(4) (LTC(4)) [5(S)-hydroxy - 6(R) - S - glutathionyl - 7,9 - trans, 11,14 - cis - eicosatetraenoic acid] and its cysteinylglycine (LTD(4)) and cysteinyl (LTE(4)) analogs, which are derived by peptide cleavage, differ in the concentrations required to elicit comparable contractions of the guinea pig ileum, with respective potencies of 1.2:5:1. The effect of the ongoing bioconversion of LTC(4) and LTD(4) on the contractile response of the guinea pig ileum to each was determined by recording the pattern of the contraction and quantitating the initial agonist and its metabolic products. The contraction was elicited by radiolabeled agonist, and its conversion products were sampled at defined intervals and resolved by their retention times on reverse-phase high performance liquid chromatography. After a latent period of 60 s. LTC(4) initiated a linear response, followed by a slower, progressive response to a maximum level that was maintained without relaxation. The metabolic conversion of LTC(4) was <5% during the linear phase of contraction and complete inhibition of bioconversion of LTC(4) to LTD(4) by the presence of serine-borate complex did not alter the pattern of the spasmogenic response. As the maximum response in the presence of serine-borate complex was three-quarters of that obtained without the inhibitor of bioconversion, the predominant response was to LTC(4) itself. The spasmogenic response of the ileum to LTD(4) was immediate, linear to a maximum level, and immediately followed by a marked relaxation. That the failure of LTD(4) to sustain a contraction was due to its immediate, rapid, and quantitative conversion to the less potent LTE(4) was established by pharmacologically inhibiting and anatomically deleting the converting activity. In the presence of L-cysteine the conversion of LTD(4) to LTE(4) was largely inhibited and the maximum contractile response was well maintained. After anatomic removal of the mucosa that contained the LTD(4) dipeptidase activity, the longitudinal smooth muscle preparation gave a maximal response to LTD(4) that was fully maintained. Thus, bioconversion is not a prerequisite for the spasmogenic activity of LTC(4) and accounts for the transient response of the ileum to LTD(4).

Animals↗
PubMed1983

Specific receptors for leukotriene C4 on a smooth muscle cell line.

Specific receptors for leukotriene C4 (LTC4) have been identified on an intact smooth muscle cell line, DDT1 MF-2 cells derived from the Syrian hamster vas deferens. Specific [3H]LTC4 binding at a fixed input at 4 degrees C was rapid, reached a plateau at 86% of total binding at 60 min, and was reversible upon addition of excess homoligand. With incremental inputs of radioligand and a constant cell number, specific [3H]LTC4 binding reached a plateau indicative of saturable binding sites. LIGAND analysis of the Scatchard plot demonstrated a single high affinity binding site with a dissociation constant (Kd) of 5 nM. With incremental inputs of unlabeled LTC4, LIGAND analysis of the Scatchard plot demonstrated a single high affinity site with a Kd of 4.4 nM and in some experiments an additional low affinity site with a Kd of 634 nM. The myotonically active structural analogues of LTC4, 5(R),6(S)-LTC4, 11-trans-LTC4, and C1-monoamide-LTC4, competed effectively with radiolabeled LTC4 such that the relative Kd values of these heteroligands were within one log of that of the homoligand. In contrast, the other native sulfidopeptide leukotrienes, leukotriene D4 and leukotriene E4, exhibited relative Kd values that were 2-3 logs less than that of LTC4. Thus, the high affinity receptor on the DDT1 smooth muscle cell line is specific for a single constituent, LTC4, of slow reacting substance of anaphylaxis.

Animals↗
PubMed1982

IgE-mediated acute asthma following inhalation of a powdered marine sponge.

IgE-antibodies reactive with extracts of a number of different marine invertebrate-species were demonstrated in the serum of a laboratory worker who experienced an acute attack of asthma following occupational exposure to powdered marine-organisms. Histamine was liberated from the patient's blood following in vitro challenge with sponge extract. The desirability of knowing the atopic status of employees in certain occupations is stressed.

Acute Disease↗