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Biomedical subjects

J M Weiler

Publications and source records attributed to J M Weiler.

At least 19 recordsLinked to original sources
PubMed1992

Eosinophil granule cationic proteins regulate complement. I. Activity on the alternative pathway.

Eosinophil granules contain several cationic proteins that mediate tissue damage in allergic disease. The present study examined the capacity and mechanisms by which these cationic proteins regulate activity of the alternative pathway of C. Eosinophil peroxidase and eosinophil cationic protein inhibited formation of cell-bound alternative pathway C3 convertase, causing 50% inhibition of lysis at about 0.19 and 0.75 microgram/10(7) cellular intermediates, respectively. Major basic protein inhibited alternative pathway C3 activity by only 19% at 1.5 micrograms/10(7) cellular intermediates. Eosinophil-derived neurotoxin had no activity on the alternative pathway. The eosinophil granule proteins were examined for the mechanism by which they inhibited alternative pathway activity. Eosinophil peroxidase and major basic protein inhibited fluid phase factor B consumption in a reaction mixture that also contained factors D and C3b, eosinophil-derived neurotoxin had no activity on factor B consumption, and eosinophil cationic protein consumed factor B in the absence of C3b and factor D. Both eosinophil cationic protein and eosinophil peroxidase enhanced the decay of preformed alternative pathway convertase. Lysis of EAC4b,3b cellular intermediates formed to contain a low surface amount of C3b was more inhibited than was lysis of cells formed with a standard amount of C3b on the surface. This suggests that these eosinophil proteins acted predominantly on C3b to regulate alternative pathway activity. We also found that none of the eosinophil granule cationic proteins had any effect on later events after the formation of the C3 convertase. We conclude that although eosinophil-derived neurotoxin (isoelectric pH value (pI) = 8.9) does not regulate alternative pathway activity, the more highly charged eosinophil granule cationic proteins--major basic protein (pI = 10.9), eosinophil cationic protein (pI = 10.8), and eosinophil peroxidase (pI = 10.8)--do share the capacity to regulate C activity and may exert this activity in vivo.

Blood Proteins↗
PubMed1992

Heparin and modified heparin inhibit complement activation in vivo.

Heparin regulates C activity in vitro, but has not been examined for this activity in vivo. The present study investigated the ability of commercial heparin and derivatized (N-desulfated, N-acetylated) heparin (Hep-NAc) with greatly diminished anticoagulant activity to inhibit C activation in guinea pigs. Catheters were placed in the right atrium of guinea pigs and kept patent with frequent saline flushes. The next day, heparin, Hep-NAc, or saline was given and 2.5 min later cobra venom factor or saline was given. Blood was drawn at intervals and assayed for total hemolytic C, C3 hemolytic activity, free hemoglobin, and activated partial thromboplastin time. Total hemolytic C and C3 activity decreased less rapidly in heparin- and Hep-NAc-pretreated animals than in non-pretreated animals, indicating that both heparins inhibited C activation. Heparin and Hep-NAc also inhibited cobra venom factor-induced hemolysis. This study demonstrates that commercial heparin and modified heparin inhibit C activation in vivo. This represents an important step in the development of an oligosaccharide drug to regulate C activation.

Animals↗
PubMed1992

Gradient polyacrylamide gel electrophoresis for determination of molecular weights of heparin preparations and low-molecular-weight heparin derivatives.

The M(r) values of pharmaceutical heparins and low-molecular-weight (LMW) heparin derivatives were examined as part of a collaborative study to develop methods for their characterization. Standard methods of M(r) determination rely on gel permeation high-performance liquid chromatography (HPLC). We report the use of gradient polyacrylamide gel electrophoresis (PAGE) to determine the M(r) values of pharmaceutical heparins and LMW heparin derivatives. This approach offers certain advantages over the HPLC method. Gradient PAGE analysis was performed in parallel, on multiple samples, with the same standard curve. HPLC was performed serially. Gradient PAGE gave higher resolution than HPLC, and thus, a mixture of easily obtained standards was used in place of individual standards for the construction of a standard curve. Heparin and various LMW heparin samples were analyzed by both gradient PAGE and conventional gel permeation HPLC methods. The number-average M(r), weight-average M(r), and polydispersity were examined by both techniques and found to be similar. This study demonstrates that gradient PAGE analysis is a sensitive method for the determination of the M(r) values of heparin and LMW heparin.

Carbohydrate Sequence↗
PubMed1992

Detection of properdin mRNA in human peripheral blood monocytes and spleen.

Properdin serves a critical role in the alternative pathway of complement by stabilizing the C3bBb complex. Early studies to determine the properdin sequence relied on amino acid sequencing of enzymatically cleaved properdin and only yielded partial sequence data. Recently Nolan et al. reported a properdin mRNA sequence obtained from the U937 myelomonocytic cell line. We sought to detect properdin mRNA in two normal human tissues and to compare those sequences with that obtained from the U937 cell line. Cytoplasmic RNA harvested from human spleen and peripheral blood monocytes served as a template for first strand synthesis. The cDNA was then used as a template for polymerase chain reaction. A properdin message was detected in both spleen and peripheral blood monocytes but not in peripheral blood neutrophils. The sequence was nearly identical to that obtained from the U937 cell line. These experiments demonstrate that peripheral blood may be used as a ready source for properdin mRNA and will faster studies to define the defect in properdin-deficient patients.

Amino Acid Sequence↗
PubMed1992

Medical modifiers of sports injury. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) in sports soft-tissue injury.

This article provides a background for the use of nonsteroidal anti-inflammatory drugs (NSAIDs) in sports medicine, including the nature of the drugs, the settings and rationale for their use, and concerns about their general safety. The criteria for the ideal study to examine the efficacy and safety of NSAIDs after acute injury is then enumerated, including a review of how many of the published studies have met each of the major criteria. Selected studies are described to demonstrate those that have or have not provided the basis for a rational decision on the use of NSAIDs in sports medicine and in the treatment of tendinitis. Finally, this article draws conclusions based on these published studies.

Acute Disease↗
PubMed1991

Antithrombin III regulates complement activity in vitro.

Heparin, a polyion, exerts its main activity to inhibit coagulation through a serine protease inhibitor, antithrombin III. Previous studies have clearly shown that heparin in the absence of antithrombin III also has the capacity to regulate C activity. The present studies examined the ability of purified human antithrombin III to regulate classical and alternative pathways of C, alone and in the presence of heparin. Antithrombin III alone inhibited generation of both pathways in a dose-related manner; antithrombin III at 8 micrograms/10(7) cellular intermediates inhibited generation of the classical and alternative pathway convertases by 60 and 42%, respectively. Antithrombin III and heparin augmented each other's capacity to inhibit generation of both convertases in a dose-related manner. Antithrombin III did not appear to inhibit on the basis of charge because it is only slightly anionic (isoelectric pH value, 5.0); instead, antithrombin III may have acted as a serine protease inhibitor of the proteolytic enzymes of the C cascades. Antithrombin III acted only to inhibit formation of the alternative pathway convertase but had no activity on terminal lysis by this pathway; similarly, antithrombin III inhibited preformed EAC1,4b,2a,3b but had no activity on classical pathway cellular intermediates containing additional components. Finally, antithrombin III inhibited consumption of factor B hemolytic activity in a reaction mixture that also contained factor D and C3b, suggesting that factor D activity was also inhibited. These studies demonstrate the capacity of antithrombin III to regulate C and suggest that, in concert with heparin, antithrombin III may play an important role in the regulation of C in vivo.

Antithrombin III↗
PubMed1990

Immobilization of C3b with retention of functional activity.

We compared eight commercially available, pre-activated affinity chromatography supports for ability to immobilize C3b that would retain functional activity. Pre-activated supports that we studied were: cyanogen bromide activated agarose, N-hydroxysuccinimide activated agarose, Reacti-Gel HW-65, Actigel A aldehyde activated agarose, thiopropyl activated agarose, 1,4-bis(2,3-epoxypropoxy) butane activated agarose, Reacti-Gel GF-2000 and tresyl activated agarose. The amount of C3b immobilized by each support varied from 81% for Actigel A aldehyde activated agarose to only 19% for Reacti-Gel GF-2000. We examined the functional capacity of the C3b immobilized on these various supports to participate in the alternative pathway. Immobilized C3b was mixed with factors D and B of the alternative pathway and examined over time for ability to consume factor B hemolytic activity. C3b immobilized on thiopropyl activated agarose consumed factor B at a rate comparable to unbound fluid phase C3b. C3b immobilized on other supports was less active in participating in factor B consumption. Thus, we have demonstrated the ability to immobilize C3b onto a solid matrix with the immobilized C3b retaining the ability to participate in the alternative pathway. This immobilized C3b can be used to fractionate substances with high C3b binding affinity.

Animals↗
PubMed1990

A prospective study of the risk of an immediate adverse reaction to protamine sulfate during cardiopulmonary bypass surgery.

Protamine sulfate administration may cause life-threatening reactions. We prospectively examined the incidence of immediate adverse reaction after protamine in 243 patients who underwent cardiopulmonary bypass surgery. Twenty-six patients (10.7%) had reactions, and 1.6% had a precipitous drop in blood pressure immediately after protamine administration. Risk factors were previous exposure to protamine, diabetes, history of receiving protamine-containing insulin, and possibly vasectomy. However, neither a positive skin test nor a positive IgE ELISA for antiprotamine antibody predicted that a patient would have a reaction. C4a levels were increased in patients who had reactions as compared with age-, sex-, and cardiac disease-matched patients who did not have reactions, suggesting a role for complement in some reactions. Immediate adverse reactions to protamine are very common, and alternative therapies are urgently needed to eliminate the use of protamine.

Adult↗
PubMed1990

Randomized, double-blind, parallel groups, placebo-controlled study of efficacy and safety of Rynatan in the treatment of allergic rhinitis using an acute model.

We conducted a randomized, double-blind, parallel groups, placebo-controlled acute study of Rynatan (8 mg chlorpheniramine tannate, 25 mg pyrilamine tannate, 25 mg phenylephrine tannate) in 104 volunteers with allergic rhinitis. Subjects reported to City Park on a Saturday morning during the height of the grass pollen season in late spring and remained in the park for eight hours that day and on the following day. Cards were completed hourly to evaluate symptoms of allergic rhinitis and adverse experiences caused by therapy. The first three cards completed on Saturday morning were used to demonstrate that each subject had had at least minimal symptoms of allergic rhinitis and to determine baseline symptoms. Rynatan or placebo was given at noon and 7:30 PM that day and at 8:30 AM the next day. Subjects completed symptom cards hourly until 4:30 PM on Saturday, three cards that evening, and eight cards hourly the next day until 4:30 PM. The group receiving Rynatan had significantly more allergic rhinitis symptom relief than the placebo group (P = .003). More subjects in the Rynatan group (34/52) reported global symptom improvement than did subjects in the placebo group (18/52, P = .002). There were no significant severe adverse experiences and no statistically significant differences between treatment groups in incidence or severity of drowsiness, dizziness, jitteriness, headache, or nausea. We conclude that Rynatan is safe and effective in treating acute symptoms of allergic rhinitis in otherwise healthy adult subjects.

Adolescent↗
PubMed1989

Anaphylactoid reactions to vascular graft material presenting with vasodilation and subsequent disseminated intravascular coagulation.

This report describes five patients who had immediate adverse reactions following placement of a vascular graft. All had unusually persistent decreases in systemic vascular resistance, and four of these patients had bleeding as an early manifestation of this reaction. In two of three patients in whom the graft was replaced, uneventful recovery followed. Both patients in whom the graft was not replaced died. Blood samples from two of the patients demonstrated activation of complement and of the kinin system, whereas control patients did not demonstrate increased levels of activation products from these cascade systems. Recognition of this syndrome is important to patient survival, which appears to depend on rapid replacement of the graft.

Aged↗
PubMed1988

Homogeneous, structurally defined heparin-oligosaccharides with low anticoagulant activity inhibit the generation of the amplification pathway C3 convertase in vitro.

This paper demonstrates that heparin-oligosaccharides with low anticoagulant activity have a high capacity to inhibit activation of the amplification pathway of complement in vitro. We prepared heparin-oligosaccharides by partial depolymerization of heparin using purified flavobacterial heparinase. The resulting oligosaccharide mixture was then fractionated using strong anion exchange-high pressure liquid chromatography to produce individual oligosaccharide components of this mixture, with degree of polymerization ranging from 2 to 16. These heparin-oligosaccharides were examined for both their anticoagulant activity and capacity to inhibit activation of the amplification pathway of complement. Although there was little difference among commercial heparins, a correlation between molecular weight and activity to inhibit convertase generation was clearly established for heparin-oligosaccharides between degree of polymerization 2 through 16. Heparin-oligosaccharides of degree of polymerization 10-16 (Mr 3888-5320) demonstrated up to 54% of heparin's activity on a molar basis (and up to 163% of heparin's activity on a weight basis) in inhibiting the amplification pathway of complement in vitro while showing almost no anticoagulant activity. These studies, for the first time, completely separate heparin's ability to inhibit complement activation from its anticoagulant activity.

Animals↗
PubMed1988

Eosinophil granule major basic protein regulates generation of classical and alternative-amplification pathway C3 convertases in vitro.

Eosinophil major basic protein (MBP), a highly charged polycation, forms the core of the eosinophil granule and mediates tissue damage in allergic disease. Purified MBP was studied for capacity to regulate the generation of classical and alternative-amplification pathway C3 convertases because previous studies have shown that other polycations (protamine, poly-L-lysine) and polyanions (heparin) may play important roles in regulating C activation. MBP inhibited the generation of EAC1,4b,2a and EAC4b,3b,Bb,P but appeared to inhibit the generation of classical pathway convertase more than the alternative amplification pathway convertase at a given dose. Dose-response curves with MBP were steeper than curves seen with polyanion (heparin). MBP did not lyse cellular intermediates at concentrations that caused almost total inhibition of convertase generation. One mechanism of inhibition of convertase generation may have been through an action on C3b, because preincubation of MBP with an EAC4b,3b cellular intermediate interfered with the ability of this cellular intermediate to be lysed. Furthermore, MBP prevented consumption of B in a reaction mixture that contained factors B, D, and C3b, also suggesting an action on C3b. Reduced and alkylated MBP (A-MBP) was compared with native MBP, which possesses two reactive sulfhydryl groups, to determine whether charge alone is responsible for blocking convertase generation; native MBP rapidly associates and is relatively insoluble at neutral and alkaline pH whereas A-MBP remains soluble. A-MBP impaired convertase generation, did not appear to remain bound to cellular intermediates and did not suppress B consumption in the fluid phase assay. This suggests that the ability of MBP to regulate C activation is complex and not entirely through its net charge. Finally, although heparin or MBP alone may prevent C activation, when these substances were present at the same time there was no effect on C activation suggesting that charge neutralization may abrogate the effects of these charged substances on C activation. Taken together, these studies suggest that MBP at physiologic concentrations may regulate in vivo C activation at the tissue level.

Alkylation↗
PubMed1988

Multicenter, double-blind, multiple-dose, parallel-groups efficacy and safety trial of azelastine, chlorpheniramine, and placebo in the treatment of spring allergic rhinitis.

Azelastine, a novel antiallergic medication, was compared with chlorpheniramine maleate and placebo for efficacy and safety in the treatment of spring allergic rhinitis in a multicenter, double-blind, multiple-dose, parallel-groups study. One hundred fifty-five subjects participated. Subjects ranged in age from 18 to 60 years of age and had at least a 2-year history of spring allergic rhinitis, confirmed by positive skin test to spring aeroallergens. Medications were given four times daily; the azelastine groups received 0.5, 1.0, or 2.0 mg in the morning and evening with placebo in the early and late afternoon; the chlorpheniramine group received 4.0 mg four times daily. Daily subject symptom cards were completed during a screening period to assess pretreatment symptoms and during a 4-week treatment period while subjects received study medications. Individual symptoms, total symptoms, and major symptoms were compared to determine efficacy of medication. Elicited, volunteered, and observed adverse experiences were recorded for each subject and compared among groups. Vital signs, body weights, serum chemistry values, complete blood cell counts, urine studies, and electrocardiograms were obtained for each subject and compared among groups. Symptoms relief in the group receiving the highest concentration of azelastine (2.0 mg twice daily) was statistically greater than in the placebo group during all weeks of the study. Lower doses of azelastine were statistically more effective than placebo only during portions of the first 3 weeks of the study. In contrast, although the chlorpheniramine group did have fewer symptoms than the placebo group during the study, the difference never reached statistical significance during any week of the study. There were no serious side effects in any of the treatment groups. Drowsiness and altered taste perception were increased significantly over placebo only in the high-dose azelastine group. Azelastine appears to be a safe, efficacious medication for seasonal allergic rhinitis.

Adolescent↗
PubMed1988

Airway reactivity to methacholine in nonatopic asymptomatic adults.

We studied 50 nonsmoking volunteers, ages 18-35 yr, with no past or present history or physical examination findings of asthma, rhinitis, allergic disease, or recent respiratory infections, to evaluate the usefulness of the methacholine bronchoprovocation challenge (MBPC) as a screening test for asthma. All were skin-test-negative to 29 aeroallergens and had base-line pulmonary function values greater than 80% predicted. Fourteen (28%) subjects had a drop in forced expiratory volume in 1 s (FEV1) of 20% or greater at a provocative dose (PD20FEV1) less than or equal to 225 breath units. Moreover, when these subjects were compared with 21 asymptomatic allergic asthmatics, there was significant overlap between the two groups in concentration of methacholine causing this decline in FEV1. A positive MBPC at methacholine concentrations less than or equal to 5 mg/ml was not diagnostic of asthma, and a negative MBPC at methacholine concentrations greater than or equal to 10 mg/ml did not rule out asthma. These data strongly suggest that MBPC should not be used as the sole factor for the diagnosis of clinically significant asthma. A positive MBPC is one indication of the presence of airway hyperresponsiveness and thus is only one of many factors that must be considered in the diagnosis of asthma.

Adult↗
PubMed1987

Airway responses to methacholine in asymptomatic nonatopic cigarette smokers.

We prospectively performed methacholine bronchoprovocation challenges on 46 young smokers to examine the effects of cigarette smoking on airway responsiveness. The subjects, ages 18-35 yr, had no past or present history or physical examination findings of asthma or other lung diseases, rhinitis, allergic diseases, or respiratory infections; were skin test negative to 29 common aeroallergens; and had base-line pulmonary function values greater than 80% predicted. Sixteen of 46 (35%) subjects had a 20% or greater drop in forced expiratory volume in 1 s at a provocative methacholine concentration less than or equal to 25 mg/ml. The degree of methacholine responsiveness was not dependent upon base-line pulmonary function values or the amount of cigarettes consumed, and there was no association between the amount of cigarettes consumed and base-line pulmonary function values. These data suggest that many young asymptomatic nonatopic smokers have increased airway responsiveness to inhaled methacholine without clinically significant hyperreactive airway disease.

Adolescent↗