Biomedical subjects

M M Glovsky

Publications and source records attributed to M M Glovsky.

At least 37 records · Page 2Linked to original sources

PubMed1988

Anaphylatoxin C3a peptide contracts human pulmonary vasculature.

Complement anaphylatoxin C3a C-terminus octapeptide Ala-Ala-Ala-Leu-Gly-Leu-Ala-Arg (C3apep) contracted both pulmonary artery (PA) and pulmonary vein (PV) in a dose-dependent manner over the concentration range of 0.1 micrograms/ml to 100 micrograms/ml with the latter having maximal contractile activity. Removal of the terminal arginine caused complete loss of activity of C3apep. Contractions consisted of an early and a sustained component with the latter component being much greater in PV than PA. The early component was inhibited by pretreatment of tissues with the cyclooxygenase inhibitor indomethacin, or the thromboxane synthase inhibitors dazoxiben or U63,557A. The sustained contractile component was inhibited by the leukotriene antagonist FPL55712 or the 5-lipoxygenase inhibitors U60,257 (Piriprost) or nordihydroguaiiararetic (NDGA). C3apep challenge of both PA and PV resulted in the generation of leukotriene C4. These results suggest that C3apep causes contraction of human pulmonary arteries and veins by the production of thromboxane A2 and leukotrienes.

Amino Acid Sequence↗

PubMed1987

Activation of human serum complement with allergens. I. Generation of C3a, C4a, and C5a and induction of human neutrophil aggregation.

To understand the relevance of allergens in generation of C3a, C4a, and C5a in normal human serum, we studied extracts of several allergens (house dust, house dust mite, Aspergillus fumigatus, and perennial ryegrass). Known complement activators zymosan and endotoxin were used as controls. Generation of C3a, C4a, and C5a (determined by radioimmunoassays) occurred with extracts of house dust and Aspergillus more than with house dust mite and ryegrass. Anaphylatoxins were produced both in dose and time-dependent fashions. Serum activated with house dust and Aspergillus extracts induced neutrophil aggregation when this serum was added to neutrophil suspensions. Less aggregation occurred when house dust mite and perennial ryegrass extract-activated sera were added to human neutrophils. We propose that some allergens may induce biologic responses by activation of sera and generation of anaphylatoxins as well as by IgE-mediated responses.

Adult↗

PubMed1987

Anaphylatoxin-induced neutrophil chemotaxis and aggregation. Limited aggregation and specific desensitization induced by human C3a and synthetic C3a octapeptides.

Human neutrophil aggregation was induced by highly purified human C3a and chemically synthetic COOH-terminal peptides of C3a (C3a-8R; Ala-Ala-Ala-Leu-Gly-Leu-Ala-Arg) in a dose-dependent manner and was 40% of human C5a-induced aggregation at each optimal concentration. In contrast to C5a and formyl-Met-Leu-Phe (f-MLP), C3a and C3a-8R showed little chemotactic activity. Specific desensitization of neutrophil aggregation was observed with C3a, C3a-8R, C5a and f-MLP, but not with C3a-des-Arg-7R, indicating that the human neutrophil has C3a-specific binding sites which are different from C5a and f-MLP receptors. An additive effect on aggregation was observed at suboptimal concentrations of C5a (1 X 10(-8) M) and C3a (1 X 10(-6) M) or C3a-8R (1 X 10(-5) M). These studies suggest that a subpopulation of human neutrophils have specific binding sites for C3a and C3a may work cooperatively with C5a during the process of neutrophil activation by increasing aggregation and lysosomal enzyme release.

Anaphylatoxins↗

PubMed1985

Immunologic studies in patients with chyluria.

Patients with chyluria, postoperative chylothorax, or surgical thoracic duct drainage are depleted of lymphocytes, IgA, and C3 as a result of the loss of lymphatic cellular and humoral elements, but the specific defects have not been well characterized. Therefore, we investigated the immunologic status of three patients with longstanding chyluria who were lymphopenic but did not have evidence of opportunistic infections. All patients had normal levels of immunoglobulins except for a moderate decrease in the IgA fraction, a normal antibody response to viral agents, and a normal hypersensitivity response to at least one of six recall antigens. Their complement levels were essentially normal. All were leukopenic because of decreased numbers of circulating lymphocytes. Two had depressed relative and absolute numbers of OKT4 (helper/inducer) T cells and normal or increased relative numbers of OKT8 (cytotoxic/suppressor) T cells, resulting in a marked reversal of the OKT4 to OKT8 ratio. The third was severely depleted of both OKT4 and OKT8 cells. The response of their peripheral blood mononuclear cells to mitogen stimulation was reduced, but they all had normal or increased absolute and relative numbers of natural killer (NK) cells as defined by HNK-1 or OKM-1. Their NK activity was less than that of normal controls unless stimulated by interferon, suggesting that many of the NK cells were immature. Normal delayed hypersensitivity, reduced but effective mitogen stimulation, and a normal NK response after interferon may be factors that protect these patients against opportunistic infections and neoplasms.

Antibodies, Monoclonal↗

PubMed1985

Regulation of human neutrophil guanylate cyclase by metal ions, free radicals and the muscarinic cholinergic receptor.

We have examined the properties of soluble guanylate cyclase activity in the human neutrophil. The enzyme showed complex regulation by metal ions. A 10-fold higher activity was observed in the presence of Mn2+ than Mg2+, while Ca2+ caused an increase in activity only in the presence of Mg2+ ion. Sodium nitroprusside (SNP), azide and hydrogen peroxide were activators of the enzyme. Dithiothreitol blocked the activation by SNP, suggesting the involvement of thiol groups in the activation process. Carbachol acting through the muscarinic cholinergic receptor caused a dose-dependent activation, which was blocked by atropine. Higher concns of carbachol were required to activate guanylate cyclase than were required for the modulation of enzyme release elicited by N-formyl-L-methionyl-L-leucyl-L-phenylalanine. Nordihydroguaracetic acid inhibited carbachol stimulation of guanylate cyclase. By contrast, trifluoperazine (TFP), a calmodulin antagonist, caused a biphasic modulation of basal activity in the presence or absence of carbachol. Our results indicate that: allosteric interactions of metal ions are important to the regulation of the enzyme, the free radical nitroxide as well as hydrogen peroxide enhances enzyme activity, agonist occupancy of the muscarinic cholinergic receptor activates neutrophil guanylate cyclase probably through a mechanism involving calcium influx and the activation of the lipoxygenase pathway, and a TFP-sensitive site (possibly calmodulin) is involved in the selective regulation of basal enzyme activity.

Azides↗

PubMed1985

Chronic chyluria: a clinical study of 3 patients.

Studies of patients with chyluria or chylothorax have demonstrated significant disruptions of protein, blood and fat metabolism that may result in iron deficiency anemia, hypoproteinemia, hypolipidemia and malnutrition. To document the sequential development of these complications we performed serial clinical and biochemical studies for 2 to 12 years in 3 patients with presumed filarial chyluria whose sole treatment had been diethylcarbamazine. Despite the chronic loss of chyle in the urine these 3 patients did not have significant complications during the period of observation. The weight and blood pressure remained stable. No persistent anemia, hypoproteinemia or hypolipidemia was noted. Except for 1 patient in whom a transient decrease of the creatinine clearance developed during pregnancy, no permanent renal function impairment occurred. These observations suggest that chronic chyluria may not always result in serious alterations of the physical status or body functions of these patients requiring surgical repair, and supports the hypothesis that untreated chyluria could be a relatively benign process in our milieu.

Adult↗

PubMed1985

Activation of the alternative complement pathway by intraocular lenses.

To determine if posterior chamber polymethylmethacrylate lenses with polypropylene loops activate complement, the authors measured levels of C3a, C4a and C5a by radioimmunoassay in human sera incubated with and without these lenses. Human sera incubated with intraocular lenses showed elevated levels of C3a and C5a but no change in C4a. There were no statistically significant differences in the generation of activated complement by polypropylene loops vs polymethylmethacrylate optics. The authors also compared the ability of intraocular lenses to activate complement with that of zymosan and endotoxin, known activators of the alternative pathway. Our results suggest that polymethylmethacrylate lenses with polypropylene loops generate C3a and C5a by activation of the alternative complement pathway.

Adult↗

PubMed1984

Identification of receptor regulatory proteins, membrane glycoproteins, and functional characteristics of adenylate cyclase in vesicles derived from the human neutrophil.

Human neutrophils were disrupted by brief sonication under conditions which preserve the hormone sensitivity of adenylate cyclase and yield minimal granule lysis. Fractions enriched in adenylate cyclase were analysed for hormonal and guanine nucleotide regulation of the enzyme as well as structural proteins. Adenylate cyclase was activated by PGE1 and isoproterenol in a GTP-dependent fashion, while f-met-leu-phe and C5a gave no stimulation. Cholera toxin treatment, which specifically modifies cyclase-related GTP-binding proteins, caused a dose-dependent enhancement of GTP activation, in which GTP alone activated maximally and PGE1 was without further effect. The following proteins were detected in the cyclase-containing vesicles: a 42 K mol. wt protein labeled selectively by cholera toxin; protein subunits observed in SDS gels at 214, 165, 105 and 47 K, of which the 47 K band was the most prominent and comigrated with actin; prominent lectin-binding activities at 165 K (concanavalin A and wheat germ agglutinin) as well as at 100 K (wheat germ agglutinin); and a set of proteins and lectin-binding activities in fractions containing beta-glucuronidase activity distinct from adenylate cyclase containing vesicles. The identification of receptor-controlled cyclase, GTP-binding regulatory proteins, cytoskeletal elements and unique lectin-binding activities in a single vesicle preparation should contribute to an understanding of receptor-mediated control of neutrophil function.

Adenylyl Cyclases↗

PubMed1984

Studies on C3ahu binding to human eosinophils: characterization of binding.

C3a purified to chemical homogeneity from human serum binds preferentially to human eosinophils greater than neutrophils. Little or no binding is found with human platelets. Maximum binding to eosinophils at 37 degrees C occurs within 15 min. Dilution of 125I-C3a by either cold C3a or washing away unbound 125I-C3a and reincubating at 37 degrees C reveals a T1/2 of approximately 30 min. C3adesArg neither binds to eosinophils nor inhibits the binding of 125I-C3a. The binding of C3a to human eosinophils may reflect a physiologic role of C3a in eosinophil motility or function.

Blood Platelets↗

PubMed1984

The beta-adrenergic receptor in the human neutrophil plasma membrane: receptor-cyclase uncoupling is associated with amplified GTP activation.

We compared the properties of the adenylate cyclase system in plasma membranes derived from gas cavitation and sonication of human neutrophils. In membranes prepared from cavitated cells, cyclase was stimulated by fluoride ion and Gpp(NH)p. Stimulation by isoproterenol (and PGE1) was absent, although the beta-receptor was present as judged by 125I-HYP binding. Two unusual characteristics of this cyclase system are a) substantial activation of cyclase by GTP in the absence of hormone, and b) reduction in the regulation of the beta-receptor by GTP. By contrast, vesicles isolated from sonicated cells displayed normal GTP-dependent activation by isoproterenol (as well as PGE1) and GTP regulation of the beta-receptor, while hormone-independent stimulation by GTP was negligible. Cholera toxin-catalyzed ADP ribosylation revealed a prominent band at 42K in both membranes, and a minor band at 35K, although the degree of labeling of this protein was lower in the "cavitated" vesicles. Our results suggest that the mode of cell lysis and membrane preparation influence receptor-cyclase interactions and that receptor-cyclase uncoupling is associated with amplified GTP activation and altered receptor regulation by GTP.

Adenylyl Cyclases↗

PubMed1984

Activated complement in inflamed aqueous humor.

Activated complement is an important mediator of inflammation. Radioimmunoassay was used to measure levels of C3a, an activated fragment of C3, in aqueous humor. Additionally, immunoelectrophoresis was performed on aqueous humor to detect Factor B and its conversion product, Bb, as well as C3c, a breakdown product of C3. All six samples of normal aqueous humor had no detectable C3a, C3c, or Factor B. All eight samples of aqueous humor from patients with anterior uveitis had measurable levels of C3a. Factor B and C3c were detected in 3/7 samples of inflamed aqueous humor. Factor B was converted fully to Bb in two of these three samples, suggesting alternative pathway activation of complement. Activated complement fragments are present in the aqueous humor of eyes with anterior uveitis and may help mediate the inflammatory process.

Adult↗

PubMed1983

Effects of particulate beta-1,3 glucan on human, rat, and guinea pig complement activity.

Particulate glucan, a beta-1,3-linked polyglucose derived from Saccharomyces cerevisiae, has been demonstrated to have a wide range of immunopotentiating effects. Glucan administration is associated with the modification of a variety of experimentally induced infectious disease states as well as the inhibition of growth of implantable and spontaneous tumors. The present study was designed to evaluate the effect of glucan upon activation of the complement system in rats and guinea pigs. Additional studies were performed to determine the in vitro activating effect of glucan and zymosan on complement activity of human serum. Glucan activated both the classical pathway of normal human sera and the alternate pathways in C2hu-deficient sera in vitro releasing anaphylatoxins such as C3a. The intravenous injection of glucan activated the alternate pathway of guinea pig plasma. The influence of glucan on complement depletion induced by cobra venom factor (CVF) was also ascertained. Complement activation by glucan may contribute, in part, to the enhanced resistance of the host against tumor growth as well as infectious episodes.

Animals↗

PubMed1982

C3a-induced lysosomal enzyme secretion from human neutrophils: lack of inhibition by f met-leu-phe antagonists and inhibition by arachidonic acid antagonists.

C3a-induced lysosomal enzyme secretion from human peripheral neutrophils in a noncytolytic, dose-dependent (10-100 microgram/ml) process. Release of both primary and secondary granule constituents occurred when neutrophils were exposed to C3a plus cytochalasin B, however, C3 alone induced limited release of lysozyme. A competitive antagonist of the formyl-peptide receptor on neutrophils, t boc (phe-leu) 2-phe, did not block the release induced by C3a. Arachidonic acid antagonists, nordihydroguaiaretic acid and quercetin caused dose-dependent inhibition of release induced by C3a plus cytochalasin B, however, lysozyme release induced by C3a in the absence of cytochalasin B was minimally affected. Indomethacin at high concentration (greater than 10(-5) M) had similar inhibitory effects.

Anaphylatoxins↗

PubMed1982

Morphological changes in human polymorphonuclear leukocytes induced by C3a in the presence and absence of cytochalasin B.

Treatment of human peripheral polymorphonuclear leukocytes(PMNs) with C3a leads to profound changes in cell morphology, along with the limited secretion of lysozyme. Simultaneous addition of C3a and cytochalasin B enhances the release of lysosomal enzymes and renders the cell morphology similar to that seen when either C5a or n-formyl peptides are added to PMNs in the presence of cytochalasin B. The morphological response of PMNs treated with C3a is considerably more heterogeneous than that induced by either C5a or n-formyl-methionyl-leucyl-phenylalanine, indicating that some, but not all, PMNs have receptors for C3a.

Cell Membrane↗

PubMed1981

Anaphylaxis after sesame seed ingestion.

Four patients with histories of systemic anaphylaxis or angioedema and urticaria after ingestion of sesame seed or sesame oil-containing products were studied for anti-sesame seed extract IgE by the radioallergosorbent test (RAST). Three of four were found to be positive. RAST inhibition after density-gradient ultracentrifugation of sesame seed extract indicates that the most active allergens appear to have molecular weights between 8,000 to 62,000 daltons.

Adult↗

PubMed1981

The association of an HLA 'asthma-associated' haplotype and immediate hypersensitivity in familial asthma.

Fifty-seven members from ten families in which one parent and at least one child have asthma were studied with dilutional skin tests and RAST to grass pollens after determination of HLA haplotypes. We found no direct evidence for linkage of a hypothetical asthma locus with HLA or for a significant association of asthma with HLA haplotypes. Linkage between the HLA loci and a gene or genes which allow for the expression of clinical asthma could neither be proven nor disproven due to the small sample size. All of the asthmatic children had positive dilutional skin tests and RAST, suggesting that atopic asthma may be genetically controlled by the HLA chromosome (chromosome 6). Nonetheless, determination of the histocompatibility antigens can increase the value of predictive risk analysis for asthma. Such a determination may be important in the early identification of a child born to a family with atopic asthma.

Adult↗

PubMed1981

Complement activation requirements for histamine release from human leukocytes: influence of purified C3ahu and C5ahu on histamine release.

The activation of human sera for histamine release by zymosan and anti-BSA-BSA complexes at equivalence was dose dependent and associated with a marked fall in CH50, C3 and C5 hemolytic activities. Heat-aggregated IgG, though able to fix greater than 90% of human CH50 activity and produce a lesser fall in C3 and C5 activities than zymosan and BSA-anti-BSA complexes, was unable to induce basophil histamine release. Chemically purified human C3a and C5a each caused histamine release from human basophils; C5a was more potent than C3a. In addition, neither zymosan nor BSA-anti-BSA complexes released histamine when incubated with homozygous C3-deficient serum. The addition of C3a and C5a at suboptimal concentrations produced an additive effect of histamine release.

Anaphylatoxins↗

PubMed1980

Identification of allergens in dog dander extract. I. Clinical and immunological aspects of allergenicity activity.

Allergenic activity of mixed dog dander extract was compared with dog serum albumin by skin testing, RAST testing and RAST inhibition. Whereas albumin is a potent allergen, additional lower molecular weight allergens determined by sucrose density gradient centrifugation and immunoelectrophoresis were found. Identification of the most potent allergens and standardization of extract used for testing and treatment is a necessary prerequisite in understanding dog dander hypersensitivity.

Albumins↗