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Biomedical subjects

A L Sheffer

Publications and source records attributed to A L Sheffer.

At least 37 records · Page 2Linked to original sources
PubMed1989

Interleukin 5 and phenotypically altered eosinophils in the blood of patients with the idiopathic hypereosinophilic syndrome.

We report that the hypodense eosinophil population in three patients with corticosteroid-unresponsive IHES was uniquely long lived ex vivo in the absence of exogenous cytokines. Serum or plasma from these patients conferred prolonged viability ex vivo to normodense eosinophils from reference donors and converted them to a functionally activated hypodense phenotype. In that antibody against IL-5 neutralized this activity in IHES serum, excessive quantities of this cytokine may account for the characteristic eosinophilia and long-lived, functionally augmented eosinophil phenotype in this disorder.

Adult↗
PubMed1989

A specific LTD4/LTE4-receptor antagonist improves pulmonary function in patients with mild, chronic asthma.

LY171883 is a new selective LTD4/LTE4-receptor antagonist. To evaluate the efficacy of LY171883, we studied 138 nonsmoking asthmatic patients, 18 to 65 yr old, in a double-blind, randomized block-design study. All patients were required to demonstrate a greater than or equal to 15% increase in FEV1 after inhaled bronchodilator use and were then randomly assigned to either LY171883 (600 mg) or placebo twice daily for 6 weeks. Assessment of efficacy was measured by inhaled metaproterenol use (mg/wk), symptoms, twice-daily peak expiratory flow, and weekly FEV1 measurements. LY171883-treated patients had improved FEV1 values upon completion of the treatment period compared with placebo recipients (p = 0.003). Metaproterenol use decreased in both groups, but treatment differences, though not statistically significant, favored LY171883 (p = 0.089). Of patients who used at least 23 mg/wk of metaproterenol (36 inhalations) at initiation of the study, those who received LY171883 used significantly less metaproterenol than those who received placebo (p = 0.007). LY171883 was well tolerated and reduced the need for a bronchodilator drug while improving pulmonary function. Results of this study support the hypothesis that leukotrienes LTD4 and/or LTE4 may be important in the pathogenesis of asthma in humans.

Acetophenones↗
PubMed1988

Anaphylaxis.

Anaphylaxis, the most emergent manifestation of allergy, is best described by its clinicopathologic alterations. Sites of involvement include skin (urticaria), upper respiratory tract (laryngeal edema), lower respiratory tract (bronchospasm), and the cardiovascular system (severe hypotension). Ultrastructural analysis of skin biopsy specimens obtained from individuals experiencing exercise-induced anaphylaxis before and immediately after exercise revealed changes indistinguishable from those observed after immunologic challenge of pulmonary mast cells, and included enlargement of the mast cell granules, solubilization (discharge) of mast cell granule contents, and merger of the granule membranes with adjacent granule membranes and the mast cell membranes. Successful reversal of anaphylaxis requires prompt recognition of symptoms and early institution of therapy. Patients prone to exercise-induced anaphylaxis should avoid any foods, drinks, or pharmaceutical agents, particularly acetylsalicylic acid, for 4, and preferably 6, hours before exercise.

Anaphylaxis↗
PubMed1987

Synthesis and release of leukotriene C4 by human eosinophils.

When human peripheral blood eosinophils isolated to 92.5% +/- 6.9 purity were stimulated with either the calcium ionophore A23187 or N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP), immunoreactive leukotriene C4 (LTC4) was initially localized intracellularly and was subsequently released to the external medium in kinetically distinguishable steps. Eosinophils were stimulated with 2.5 microM A23187 in the presence of 20 mM L-serine, a hypochlorous acid scavenger that prevents the oxidative metabolism of sulfidopeptide leukotrienes. Total production of immunoreactive LTC4, the sum of intra- and extracellular LTC4, was complete within 5 to 10 min. At 5, 10, and 30 min, 65.9% +/- 15.2, 42.3% +/- 24.3, and 5.5% +/- 3.9, respectively, of the total amount of LTC4 measured remained intracellular as detected after the media and cells were separated and the latter was extracted with methanol. The time course for the intracellular synthesis and extracellular release of immunoreactive LTC4 from eosinophils pretreated with 5 micrograms/ml cytochalasin B and stimulated with 0.5 microM FMLP was like that obtained with ionophore, although the total LTC4 production was only approximately 10%. The identity of the intracellular LTC4 was confirmed by elution with reverse-phase high pressure liquid chromatography followed by scanning UV spectroscopy, radioimmunoassay, and bioassay. Eosinophils that were stimulated with A23187 in the absence of L-serine metabolized newly synthesized LTC4 to 6-trans-LTB4 diastereoisomers and subclass-specific diastereoisomeric sulfoxides that were identified only in the extracellular medium. Thus the response of purified eosinophils to two different stimuli demonstrates a transient intracellular accumulation of biologically active LTC4, the distinct extracellular release, and the apparent limitation of oxidative metabolism to the extracellular location.

Arachidonic Acids↗
PubMed1987

Morphologically distinctive forms of cutaneous mast cell degranulation induced by cold and mechanical stimuli: an ultrastructural study.

To determine whether morphological differences in the response of cutaneous mast cells characterize clinically distinct forms of urticaria, we used ultrastructural techniques to examine skin biopsy specimens from three patients with cold-induced urticaria and four patients with dermographism. Biopsy specimens were obtained before application of the stimulus and at the time of lesion formation. Patients with cold-induced urticaria exhibited morphological alterations only after stimulus application consisting of enlargement and uniform disorganization of some, but not all, granules, fusion of the membranes of adjacent granules, fusion of granule membranes with mast cell membranes, and discharge of electron-lucent and disorganized granule contents into the extracellular space. Mast cells from patients with immediate as well as delayed dermographism exhibited alterations before and after stimulus application consisting of enlargement of most granules, nonuniform (zonal) disorganization or solubilization of granule contents, fusion of granule membranes with mast cell membranes, and extracellular discharge of granule contents. Small cytoplasmic vesicles containing disorganized granular material were associated with the degranulation process. Endothelial cells lining nearby postcapillary venules exhibited prominent perinuclear condensation of contractile microfilaments during degranulation in both groups. Both before and after application of the stimulus, the walls of the superficial dermal vessels of the patients with dermographism were thinner and contained less extracellular matrix material than vessel walls of the patients with cold-induced urticaria. The morphologically distinctive types of mast cell degranulation that characterize these two clinically separable urticarial disorders may indicate different pathogenic mechanisms of lesion formation.

Adolescent↗
PubMed1987

Hereditary angioedema: a decade of management with stanozolol.

Thirty-seven patients with hereditary angioedema, who, without therapy, had attacks of cutaneous angioedema, gastrointestinal colic, and/or upper respiratory symptoms at a frequency and severity sufficient to prompt treatment with an attenuated androgen, have been evaluated for the incidence of side effects and biochemical toxicity during various schedules leading to the minimal effective dose. Stanozolol was administered in a 2 mg daily dose, initially, and after the symptoms and signs were adequately controlled for 2 months at this dose or at 1 mg per day, the drug was administered every other day at 4 mg. Patients who responded adequately to this schedule were administered 2 or 1 mg every other day, and then the interval between doses was gradually increased to 1 week, after which the agent was stopped. Eighteen patients experienced adverse reactions to stanozolol while the minimal effective dose was attained. In each instance the side effect subsided with a reduction in dosage. The most common adverse reactions were biochemical evidence of hepatic dysfunction and, to a lesser extent, hirsutism and menstrual irregularities. Although 21 of 27 patients in an initial study of the minimal effective dose were maintained with daily therapy in 1980, by 1986 this group and 10 additional patients were distributed so that three patients were receiving daily maintenance, 18 were receiving alternate-day maintenance, and 16 patients were receiving no maintenance therapy [corrected]. Thus, stanozolol appears to be a safe and effective agent for management of hereditary angioedema when patients are continually monitored to define the minimal effective dose or the feasibility of stopping the drug.

Adolescent↗
PubMed1985

Anaphylaxis.

Explore the source record for details and available documents.

Anaphylaxis↗
PubMed1985

Acquired deficiency of the inhibitor of the first component of complement: report of five additional cases with commentary on the syndrome.

The association of late onset recurrent angioedema with a deficiency of the inhibitor of the first component of complement (C1INH) and of the binding subunit of the first component, Clq, defines the syndrome of acquired C1INH deficiency. The description of five new cases, along with the original two and the 18 others in the literature, brings the total reported cases to 25 and highlights the associated B cell abnormalities that are present in 23 and are of a malignant nature in 19 cases. In three of the five newly reported cases, the occurrence of angioedema, which prompted recognition of the acquired deficiency of C1INH, C1q, and C4, preceded the delineation of the underlying B cell malignancy by 2 to 3 yr despite efforts to recognize neoplastic disease in two of these patients throughout the interval. Because the acquired C1INH deficiency reflects increased catabolism rather than impaired biosynthesis, only high-dose attenuated androgens elicit a measurable increment in serum C1INH. The occurrence of the syndrome with multiple myeloma is noted for the first time.

Aged↗
PubMed1985

A multicenter trial of the prophylactic effect of ketotifen, theophylline, and placebo in atopic asthma.

Three hundred seventy-four patients with asthma were entered into a year-long, double-blind, double-placebo controlled study comparing the prophylactic effect of ketotifen (229 patients), theophylline (73 patients), and placebo (72 patients). The ketotifen group was larger to allow the accumulation of additional long-term safety data. The primary measure of therapeutic effect was a decrease in concomitant medication without a significant increase in symptomatology or a decrement in pulmonary functions. A patient daily diary was used to document symptoms (cough, shortness of breath, and wheeze) and concomitant medications taken during the 2-week baseline and the subsequent 12 monthly periods. After 2 months of study-drug therapy, the ketotifen patients had a greater decrease in both concomitant medication and symptomatology than either of the other groups. This delay in the onset of therapeutic activity has been observed in other studies and is characteristic of this compound. The principal side effect observed with ketotifen is initial sedation, which was found to be self-limiting and of little concern to the patient after the first month.

Adolescent↗
PubMed1985

Exercise-induced anaphylaxis: a serious form of physical allergy associated with mast cell degranulation.

Exercise-induced anaphylaxis (EIA) is a unique and an increasingly recognized syndrome consisting of premonitory symptoms and signs of generalized body warmth, pruritus, and erythema, which progresses on continued exertion to confluent urticaria, laryngeal edema with stridor or hoarseness, and gastrointestinal colic and frequently culminates in vascular collapse. Previous studies of five individuals with this condition have demonstrated significant elevations of serum histamine concurrent with the early clinical manifestations after experimental exercise. To assess relevant morphologic alterations in the skin of these patients, cutaneous mast cells were examined by light and transmission electron microscopy before and during the initial erythema elicited by exertion. The marked alterations observed in mast cells immediately after exercise consisted of (1) loss of electron density and internal substructure of granules, (2) fusion of granule membranes with those of adjacent granules and with mast cell membranes creating conduits to the extracellular space, and (3) an apparent decrease in the number of intact granules per cell. Biopsy specimens obtained before exercise from patients with EIA and from two normal individuals who served as control subjects were identical, and the control subjects had normal mast cell morphology after exercise. Serum histamine levels were significantly elevated in patients with EIA after exercise at the time of biopsy, whereas control subjects had normal levels. These observations provide evidence that EIA is a distinct form of physical allergy associated with mast cell degranulation similar in morphology to that of human pulmonary mast cell IgE-Fc-dependent activation secretion. Characterization of this disorder is important because its prevalence may be underestimated, and its clinical consequences, which may include some morbidity, are not fully known.

Adult↗
PubMed1984

Management of adverse drug reactions.

Successful management of adverse drug reactions requires early identification and prompt treatment of anaphylaxis, whether due to immunoglobulin (Ig) E- or non-IgE-mediated mechanisms of mast cell mediator release. Acute therapy is directed toward enhancement of oxygenation and maintenance of normotension. Requisite measures include the use of epinephrine, oxygen, and adequate fluid replacement; in some instances, vasopressors or corticosteroid drug therapy may be warranted. Emergency measures may be needed to maintain the airway. Although the offending drug is usually discontinued, a necessary drug for which there is no satisfactory alternative occasionally may be continued without danger of further anaphylaxis as long as therapy is not interrupted. Other nonemergent adverse drug reactions requiring an early decision include accelerated urticarial and late maculopapular eruptions, in both of which the patient may tolerate a necessary drug with schedule manipulation. Differentiation of an adverse drug reaction from problems unrelated to the drug is essential so that needed medication is not inappropriately discontinued. Good management also requires anticipation of adverse reactions whenever a therapeutic program is instituted. Familiarity with the drug groups most commonly responsible for immunologic reactions is helpful, as is knowledge of satisfactory alternatives for these drugs in the presence of known hypersensitivity. An adverse reaction can often be minimized through use of established protocols for premedication. Desensitization, when essential, may be achieved for most drugs with graduated dosage schedules and maintained through continued administration of the drug. Identification to avoid inadvertent exposure to agents that have caused immunologic reactions in the past is essential.

Anaphylaxis↗
PubMed1984

Exercise-induced anaphylaxis.

Exercise-related anaphylaxis is a novel form of physical allergy that is being recognized with increasing frequency in a society with a growing commitment to health through planned exercise. The clinical manifestations progress from pruritus, erythema, and urticaria to some combination of cutaneous angioedema, gastrointestinal and laryngeal symptoms and signs of angioedema, and vascular collapse. The finding of an elevated serum histamine level during experimentally-induced attenuated attacks indicates mast cell participation, as in a physical allergy, and the signs and symptoms are characteristic of a classic anaphylactic reaction to a foreign substance in an allergic human.

Adolescent↗
PubMed1983

Exercise-induced anaphylaxis: a distinct form of physical allergy.

Seven individuals with exercise-induced anaphylaxis under natural circumstances, characterized by the appearance of pruritic cutaneous erythema and urticaria and associated vascular collapse and/or upper respiratory tract symptoms and signs of angioedema, were subjected to a controlled period of exercise in a laboratory. Experimental challenge consisted of running in an occlusive suit on a treadmill of moving grade with maintenance or acceleration of speed for 5 to 17 min. Cutaneous pruritus and erythema without urticaria developed in four of the subjects and progressed to angioedema in two of them; the other three subjects were unaffected. Repeat challenge of three of the abnormal responders elicited a clinical response similar to that of the previous exercise challenge. In those subjects with a clinical response to exercise challenge, mean change from baseline levels of histamine to peak levels was 7.0 +/- 3.0 ng/ml (mean +/- SEM), whereas in the group without clinical symptoms the mean change from baseline was an increase of 0.6 +/- 1.6 ng/ml (mean +/- SEM). The abnormal elevations in serum histamine during the seven exercise-induced symptomatic episodes returned to normal in about 20 min while clinical signs were also subsiding. There were no changes in pulmonary function. Exercise-induced anaphylaxis is clinically separable from cholinergic urticaria and represents a distinct form of physical allergy.

Adolescent↗