Search PubMed⌕ Search

Biomedical subjects

S R Findlay

Publications and source records attributed to S R Findlay.

At least 37 records · Page 2Linked to original sources
PubMed1984

Anti-immunoglobulin induced histamine release from naturally abundant basophils in the snapping turtle, Chelydra serpentina.

The dose response, temperature sensitivity, time course and calcium dependency of histamine release from snapping turtle basophils treated with rabbit anti-turtle immunoglobulin (RATIg) sera was explored. This investigation indicated that the level of histamine release induced by RATIg was dependent upon the concentration of RATIg with concentrations of 350 mcg/ml inducing optimal release. In addition, release was temperature dependent with release increasing over a temperature range of 10 degrees C to maximal at 27 degrees C. Release was also dependent on the length of exposure to RATIg. Release increased steadily over a time period of 0 to 30 minutes with the higher concentrations of RATIg inducing the most rapid release. Basophil-histamine release was also found to be calcium dependent. This study indicates that the snapping turtle basophil possesses similar characteristics to that of its mammalian counterparts. It is proposed that the very wide temperature range over which turtle basophils release histamine is an important feature in he immune resistance of this ectothermic animal.

Animals↗
PubMed1983

Purification of human basophils by negative selection.

Enriched populations of human basophils were prepared using a combination of negative selection techniques. First, a 2-step discontinuous gradient was made using 65% and 55% isotonic Percoll. Purification of plasma basophils by centrifugation through the gradient increased basophils from 0.96 +/- 0.55% to 14.6 +/- 7.9% (n = 9). In 5 other experiments a second step was added in which contaminating mononuclear cells were removed using a panning technique. In this technique, Percoll separated cells were treated with anti-T-cell antibodies. Contaminating T-cells were selectively removed by adherence to a petri dish coated with affinity purified goat anti-mouse IgG. Basophil purity was increased to 34 +/- 15% using this step. These experiments demonstrated that negative selection techniques can yield an increase in basophil purity 50-100-fold. The purified basophils contained the expected quantity of histamine (1.36-1.54 pg/basophil) and released the same amount of histamine in response response to different concentrations of goat anti-human IgE Fc as did unpurified cells.

Antibodies, Monoclonal↗
PubMed1983

Allergens detected in association with airborne particles capable of penetrating into the peripheral lung.

Extrinsic asthma is caused by exposure to airborne allergens. The diameter of airborne particles influences the depth of penetration and deposition fraction in the lung. In this study, we used an Andersen sampler to collect 9 different size ranges of airborne particles from a cat-containing and a cat-free room. We detected cat allergen 1 (CA1), the major cat allergen, using a rocket immunoelectrophoretic technique in larger particle size ranges (more than 5 mu). Using in vitro cat allergic donor basophil histamine release, cat-associated allergen activity was detected in particle size ranges from 10 to less than 1 mu in aerodynamic diameter. Control collections of airborne particles from a cat-free room showed little or no allergen activity, and nonatopic donor basophils did not release histamine in response to any of these samples. The P-K test (positive transfer test) confirmed findings of the other assays. We conclude that cat-derived allergens are associated with a large range of airborne particle sizes that penetrate into the peripheral lung.

Air↗
PubMed1983

Naturally abundant basophils in the snapping turtle, Chelydra serpentina, possess cytophilic surface antibody with reaginic function.

Basophils constitute 50 to 63% of the blood leukocytes in Chelydra serpentina, the snapping turtle. Immunoglobulin (Ig) on the surface of the turtle basophil was detected by indirect immunofluorescence by using an IgG fraction from rabbit anti-turtle Ig serum (RATIg) and a fluoresceinated goat anti-rabbit antibody incubated at 4 degrees C. However, when the cells were incubated with RATIg at 22 degrees C, the basophil number, as determined by Wright's stain and neutral red counts, decreased dramatically. This morphologic evidence of degranulation was directly proportional to the antiserum concentration. Degranulation also correlated with cell histamine release (r = 0.73). In other experiments, turtle basophils were found to express antigen-specific surface Ig after immunization with sheep red blood cells (SRBC). Washed basophils from immunized turtles formed basophil-SRBC rosettes in vitro. Basophils from control turtles did not. Basophil-SRBC rosettes could also be induced by in vitro passive sensitization by preincubation of normal turtle basophils in the SRBC immune turtle sera. This study shows clearly that the turtle basophil has an immune capacity analogous to the mammalian basophil/mast cell. This study also contains the first direct evidence for the existence of reaginic antibody (or antibodies) in an ectothermic vertebrate. Finally, C. serpentina is proposed as a unique animal model for the study of basophil function.

Animals↗
PubMed1983

Direct effect of complement factor C5a on the contractile state of isolated smooth muscle cells.

The complement-(C) derived factor C5a has long been recognized as a potent contractile agonist in smooth muscle (1,2); however, controversy remains as to whether the effects of this anaphylatoxin are direct or secondary to the release of histamine (3) and/or other mediators (4-8) from nonmuscle cells within the tissue. To resolve this controversy, we have assessed the contractile effects of purified human C5a and C5a des Arg in a homogeneous preparation of enzymatically dispersed smooth muscle cells derived from the stomach of the toad, Bufo marinus. This preparation, which is insensitive to histamine at concentrations as high as 10(-4) M, responds normally to a variety of electrical (9), mechanical (10), and pharmacologic (11, 12) stimuli. These smooth muscle cells also respond to purified human anaphylatoxin; exposure to the cells to purified human C5a or C5a des Arg produce contractions of the smooth muscle cells that are accompanied by increased Ca2+ influx. The contractile response was unaffected by antagonists to histamine or acetylcholine but was reduced by 30% by pretreatment with the leukotriene antagonist FPL55712. A direct contractile effect of C5a on amphibian smooth muscle cells is suggested.

Animals↗
PubMed1982

Pneumocystis carinii and cytomegalovirus pneumonia in a previously healthy adult.

A case of Pneumocystis carinii pneumonia and cytomegalovirus infection occurring in a previously healthy adult male homosexual who was not receiving known immunosuppressive therapy is described. This 35-year-old man had been treated with metronidazole and tetracycline for an intermittent diarrheal illness of 5 months' duration. He was then admitted to the hospital where he was found to have a small infiltrate in the left lower lobe, and this process soon involved both lungs. Initially, Pneumocystis carinii infection and later cytomegalovirus infection were diagnosed by lung biopsy and culture. Peripheral blood lymphopenia was present and he had in vivo and in vitro abnormalities of his cellular immune responses. He was unresponsive to Bactrim as well as pentamidine and pyrimethamine therapy and died 7 wk after hospitalization.

Adult↗
PubMed1981

Local heat urticaria/angioedema: evidence for histamine release without complement activation.

A 42-yr-old white woman reported onset in 1976 of local pruritus, burning, erythema, and edema within minutes after exposure in heat. With more extensive exposure, she occasionally had transient headaches and nausea. In order to investigate the etiology of this condition, her forearm was exposed to water at 44 degree C for 4 min. Within a few minutes, a lesion identical to her spontaneously induced ones developed only at the area exposed to heat. Samples of venous blood from this extremity demonstrated a transient rise in plasma histamine levels without any significant change in serum hemolytic complement activity or in C3, C4, or factor B. These findings suggest that this rare syndrome involves local activation of mediator release from mast cells, without participation of the complement system.

Adult↗
PubMed1981

Contraction of guinea pig ileal smooth muscle by acetyl glyceryl ether phosphorylcholine.

Acetyl glyceryl ether phosphorylcholine (AGEPC) is a chemical that has the biological activity of what was formerly termed platelet-activating factor. We report here that synthetic AGEPC induces the contraction of guinea pig ileal smooth muscle. Antagonists of histamine, acetylcholine, and slow-reacting substances (SRS) do not block AGEPC-induced contraction. These responses were long lasting, resistant to washing, and displayed complete agonist specific desensitization. Histamine- and SRS-induced contractions were unaffected by AGEPC. These studies show that AGEPC has the potential to produce a component of anaphylactically induced smooth muscle contraction.

Animals↗
PubMed1981

Hyperosmolar triggering of histamine release from human basophils.

Idiopathic reactions occurring during the infusion of hyperosmolar solutions, such as radiocontrast dyes, cause a significant number of deaths each year. These reactions are similar to those which follow mediator release during allergen-induced anaphylaxis. In attempting to explain these nonimmunologic reactions, we examined the direct effect of hyperosmolarity on normal human basophils with emphasis on release induced by mannitol. The cells of all donors released histamine in vitro in response to hyperosmolar (0.2-0.7 M) solutions of a number of solutes including mannitol. That this was not a toxic process was supported by a number of criteria, including inhibition of release by excess stimulus at 37 degrees C and a lack of release at 4 degrees C. Furthermore, electron microscopic studies revealed that hyperosmolar stimulation did not disrupt the cell membrane or lead to any signs of cytotoxicity. In contrast to antigen-stimulated release, where granules fuse only with the cell membrane, granules in mannitol-stimulated cells, in addition to fusing with the cell membrane, may also be extruded into a common intracellular sac before exteriorization. Characteristics similar to antigen-induced histamine release included the time-course for release, inhibition by drugs that modify phospholipid metabolism, p-bromophenacyl bromide, and eicosa-5,8,11,14-tetraynoic acid, and augmentation of release by deuterium oxide (D(2)O). The release process differed from antigen-induced release by a number of criteria, including independence from immunoglobulin (Ig)E-related mechanisms, insensitivity to agonists that elevate intracellular cyclic AMP, minimal dependence on extracellular calcium, lack of inhibition by 2-deoxyglucose and theophylline, and a temperature optimum of 32 degrees C. We conclude that this noncytotoxic hyperosmolar release process is different from IgE-mediated secretory events and may well play a role in the idiopathic reactions which occur secondary to the infusion of hyperosmolar solutions in man.

Adult↗
PubMed1981

Mechanisms of contraction induced by partially purified slow reacting substance from human polymorphonuclear leukocytes and leukotriene D in guinea pig ileal smooth muscle.

On the basis of the experiments described here, we suggest that the mechanism of action of SRS in guinea pig ileal longitudinal muscle is very similar to that used by other agonists in this preparation, namely interactions at a specific receptor to activate Ca++ channels leading to Ca++ influx and mechanical response. SRS responses differ in 1 important respect from those produced by other agonists. SRS and leukotriene D cause the generation of a slower contraction, which has a greater resistance to reversal by washing. The basis for this unique and prolonged duration of action is unknown but may represent an exceptionally tight, or even irreversible, association with a membrane component. Current studies on the structure of SRS may be helpful in this regard. Although not definitive, this report clearly indicates that a SRS "receptor" is, in fact, present on smooth muscle and that it utilizes a pool of calcium channels common to all smooth muscle agonists.

Animals↗
PubMed1981

Modulation of histamine release from human basophils in vitro by physiological concentrations of zinc.

Zinc, at physiologic concentrations, inhibits in vitro histamine release from human basophils induced by several immunologic (i.e., antigen and anti-immunoglobulin E (IgE) and nonimmunologic [Ca++ ionophore A23187 and formylated tripeptide formyl-methionyl-leucyl-phenylalanine (f-met peptide)] stimuli in a dose-dependent manner. Inhibition begins at about 10(-6) (ionophore A23187, anti-IgE and antigen) or 10(-5) M (f-met peptide) and is maximum at 10(-4) M (80--100% inhibition of histamine release). The activity of zinc is about 25-fold greater with respect to ionophore A23187 (ID50 = 1.1 x 10(-6) M) than to f-met peptide-induced (ID50 = 4 x 10(-5) M) histamine release. Its activity on IgE-mediated histamine release is intermediate between these two extremes (ID50 = 9.7 x 10(-6) M). Zinc does not affect the first stage of histamine release but acts on the calcium-dependent second stage. It is a competitive antagonist of the action of Ca++ in histamine secretion induced by antigen, anti-IgE and f-met peptide (but not by A23187) with a dissociation constant of about 1.2 x 10(-5) M. The addition of colchicine with zinc fails to increase the inhibition caused by the ion alone, suggesting the two compounds work via a common mechanism of action. Deuterium oxide reversed, in a dose-dependent manner, the inhibition of histamine release caused by zinc. These results suggest that the effect of zinc on histamine release from human basophils may be related to its influence on the microtubule system, directly or via its interaction with calcium.

Allergens↗
PubMed1980

Basophil "releasability" in patients with asthma.

This study was based on the premise that mediator release plays a role in the pathogenesis of allergen-induced as well as nonallergen-induced asthma. We studied histamine release from human basophils obtained from patients with asthma and from control subjects. These cells were challenged with several different stimuli: goat anti-human IgE-Fc, C5-peptide, N-formyl-methionyl-leucyl-phenylalanine (f-met peptide), Ca++ ionophore A23187, hyperosmolar mannitol, and D2O. Release induced by any one stimulus was unrelated to the response to any other stimulus. The basophils of patients with asthma and control subjects responded similarly to most stimuli: they were significantly less responsive to C5-peptide and f-met peptide, and significantly more responsive to D2O. The results suggest that there is a parameter of releasibility that must be defined for each separate stimulus, and that patients with asthma can be differentiated from normal persons by the response of their basophils to selected stimuli.

Adult↗
PubMed1979

Effect of solvent on the histamine-releasing, enzyme-releasing, and mitogenic properties of the calcium ionophore A23187.

The potency of the calcium ionophore A23187 in inducing three activities of human leukocytes (histamine secretion from basophils, enzyme secretion from PMNs, and proliferation of lymphocytes) was markedly dependent on the solvent (DMSO versus ethanol versus aqueous buffer) used for its initial sonication. While 0.1 micrograms/ml of DMSO- and ethanol-solubilized A23187 induced maximal histamine release from basophils and histaminase release from PMNs, concentrations of aqueous buffer-sonicated ionophore of greater than or equal to 1 microgram/ml were required for an equivalent response. Ionophore sonicated in organic solvents caused a maximum release of 40% of PMN beta-glucuronidase, at an optimal concentration tenfold higher than that required for maximal histaminase release; ionophore sonicated in aqueous buffers, even at high concentrations, effected a release of less than 5% of cellular beta-glucuronidase. A23187 also induced lymphocyte proliferation over a narrow concentration range; 0.05 micrograms/l of DMSO-sonicated ionophore induced optimal proliferation and concentrations greater than or equal to 0.2 micrograms/ml were toxic. Twofold higher concentrations of ethanol-sonicated ionophore and fourfold higher concentrations of aqueous-sonicated ionophore were necessary for maximal proliferation, and the magnitude of the maximal response with aqueous-sonicated A23187 was only one-half that of DMSO-solubilized agent. Ionophore-induced release of histamine from basophils and enzymes from PMNs was not cytotoxic, since ionophore induced neither LDH nor histamine release from heat-treated (47 degrees C) cells. These results explain several previous, discordant reports on the presence or absence of an effect of A23187 on cellular secretory events, on differing dose-response relationships, and on cytotoxic versus noncytotoxic mechanisms of action.

Anti-Bacterial Agents↗
PubMed1979

Augmentation of antigen-stimulated histamine release from human basophils by serum-treated zymosan particles. II. Dependence on IgE-mediated release.

It was observed previously that serum-treated zymosan particles (Zx) augmented antigen and anti-IgE stimulated histamine release. With most of the enhancement attributed to an increased rate of release, this suggested that Zx was active only during the course of IgE-mediated release. This association between IgE-mediated histamine release and responsiveness to Zx was examined further in the present report. Addition of Zx at various time intervals after release had been initiated indicated that the basophil responsiveness to Zx was limited in duration; maximum responsiveness to Zx correlated closely with the period in which the rate of IgE-mediated histamine release was maximum. The time-dependent decline in sensitivity to Zx paralleled the kinetics for desensitization to antigen. Addition of Zx failed to cause release from basophils desensitized in vitro or from basophils of a donor who failed to release histamine upon challenge with anti-IgE. In contrast to the enhancement of IgE-mediated release, Zx did not augment histamine release caused by C5a or the synthetic peptide f-Met-Leu-Phe. It is concluded that an obligatory link exists between ongoing IgE-mediated histamine release and enhancement by Zx.

Antigens↗
PubMed1979

Adenosine receptor on human basophils: modulation of histamine release.

Adenosine, at physiologic concentrations, inhibits in vitro IgE-mediated human basophil histamine release in a dose-dependent fashion. The inhibition dose-response curve is paralleled by an adenosine-induced increase in cAMP levels of human leukocyte preparations. Further evidence that the adenosine effect is related to changes in cAMP levels is that the nucleoside inhibits only in the first stage of antigen-induced histamine release and fails to inhibit the release caused by ionophore A23187. A poorly metabolized derivative of adenosine, 2-chloroadenosine inhibits as effectively as adenosine; dipyridamole, which blocks adenosine uptake, does not impair the inhibition caused by adenosine. Finally, theophylline, which is a competitive antagonist of adenosine in human lymphocytes also blocks the inhibition of release caused by adenosine. These data suggest that adenosine acts via a specific cell-surface receptor linked to adenylate cyclase. It appears that the human basophil has a specific receptor for adenosine and that this nucleoside may modulate the in vivo release of the mediators of immediate hypersensitivity reactions.

Adenosine↗
PubMed1977

Neuropathy presenting as prolonged dyspnea. Case report and review of literature.

Polyneuropathy presented as isolated respiratory muscular paralysis. Transdiaphragmatic pressure measurements, nerve conduction studies, electromyography, and biopsy of intercostal muscle confirmed the nature of the process. Patients with unexplained respiratory insufficiency must be carefully evaulated for underlying neuromuscular disease.

Adult↗