Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P15088 (mast cell)
 14,925 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine the uniformity of response by mast cells in the rat eyelid, doses of compound 48/80 ranging from 50 to 1,000 micrograms in a 10-microliters drop were applied to one eye of 30 male Sprague-Dawley rats. Phosphate-buffered saline (PBS) was applied to the other eye. Every mast cell was counted throughout microscopic slides of the tissue of the lower eyelids. Both the position and degree of degranulation of every mast cell in each slide were recorded on schematic representations of the lower eyelid. Before histologic examination, animals were observed for clinical signs of ocular anaphylaxis. Doses of 50 and 150 micrograms had no observable clinical effect. At greater doses, edema of the lids and conjunctiva increased with dose. Doses less than 250 micrograms had no significant effect on the number of mast cells or degree of degranulation. Doses of more than 250 micrograms induced degranulation in approximately 50% of the eyelid mast cells. The degree and pattern of degranulation did not change with doses greater than 250 micrograms. The morphology of degranulated mast cells treated with 1,000 or 250 micrograms of compound 48/80 was indistinguishable. We conclude that once maximal stimulation for degranulation is achieved, higher levels of compound 48/80 will not increase the level or change the type of degranulation. In addition, the maximal level of degranulation varies from one mast cell to the next. Mast cells in close proximity may differ markedly in their level of maximal degranulation, with responses ranging from no degranulation to severe degranulation with exocytosis.
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PMID:Morphologic evidence that compound 48/80-challenged rat eyelid mast cells differ in their states of maximal degranulation. 247 97

A single application of the mast cell secretagogue compound 48/80 to the surface of the rat eye induces significant histologic changes. Ocular anaphylaxis is usually the result of repeated, not single, exposures to allergenic substances. The response of conjunctival mast cells to repeated daily applications of compound 48/80 was, therefore, evaluated. Ninety rats received one dose of compound 48/80 or phosphate-buffered saline almost daily for 17 days. The frequency and degree of mast cell degranulation and the number of mast cells and other inflammatory cells in the subepithelial conjunctiva were determined histologically. The clinical response was most marked after one application of compound 48/80; repeated daily applications markedly reduced the clinical response. In eyes treated with multiple applications, 75% fewer mast cells were observable in the conjunctiva by light microscopy compared with phosphate-buffered saline treated eyes. Most mast cells were granulated; a few showed mild to moderate degranulation. Except for epithelial damage, no tissue injury was associated with multiple applications of compound 48/80. In contrast to conjunctivae subjected to a single application of compound 48/80, conjunctivae receiving multiple applications resembled that of phosphate-buffered saline controls.
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PMID:Response of rat conjunctival mast cells to multiple versus single applications of compound 48/80. 248 Dec 51

Rat mast cell granules were obtained by sonication of highly purified rat mast cells and isolated in a Percoll gradient. Phosphorylation of endogenous phosphatidylinositol in rat mast cell granules, which is catalyzed by phosphatidylinositol kinase in the granules, was assayed by measuring the incorporation of 32P from [gamma 32P]ATP into phosphatidylinositol 4-phosphate. Lipids were isolated with methanol/chloroform/HCl and were separated by thin-layer chromatography on oxalic acid impregnated silica gel plates. Phosphatidylinositol 4-phosphate areas were identified by staining with iodine, scraped and measured for 32P radioactivity. The phosphorylation reaction was inhibited by 50-500 microM adenosine, ADP and 500 microM AMP in a concentration-dependent manner. Among several anti-allergic drugs investigated. 100-1000 microM theophylline and 10-100 microM azelastine inhibited the phosphorylation reaction, but disodium cromoglycate and ketotifen had little effect.
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PMID:Inhibitory effect of adenine nucleotides and anti-allergic drugs on phosphorylation of phosphatidylinositol in rat mast cell granules. 257 58

Mechanism of inhibition of mast cell anaphylaxis by P. kurroa-extract (PK) treatment in rats was investigated. Mast cell-IgE binding, assessed from induction of passive sensitization, was not affected. Calcium-independent early activation events in mast cell anaphylaxis indicated on inhibitory influence of PK-treatment. Inhibition of membrane-protease release by PK-treatment was suggested by study of gastric secretion and exhibition of saturable synergism with Di-isopropyl fluoro phosphate on inhibition of anaphylactic degranulation. pH-independence of mast cell stabilizing effect negates any PK-influence on phospholipid transmethylation. The results complement findings of earlier studies on indirect effects of PK through alteration of membrane structure/function.
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PMID:Immunopharmacological studies on Picrorhiza kurroa Royle ex Benth. Part VI: Effect on anaphylactic activation events in rat peritoneal mast cells. 266 36

Attenuation of the rat conjunctival response by repeated topical challenge with dinitrophenyl (DNP) hapten was demonstrated in our study. Adult rats were immunized by intraperitoneal injections of dinitrophenylated Ascaris suum extract (DNP-Asc) and alum. Serum levels of anti-DNP homocytotropic antibody were determined by passive cutaneous anaphylaxis in rats prepared with antibody 48 hours earlier. In other animals, topical challenge was performed by applying N,N'-di-2,4-DNP-L-lysine (di-DNP-lysine) in phosphate-buffered saline (PBS) to one eye; PBS alone was applied to the fellow eye. The degree of conjunctival reaction was assessed clinically, and ocular tissues were processed for histological evaluation. The intensity of the conjunctival reaction and extent of mast cell degranulation were significantly greater after one challenge with di-DNP-lysine than after multiple challenges. In the multiple-challenge group, the contralateral eye remained responsive to a single challenge with di-DNP-lysine. These results may have implications for therapeutic interventions in ocular anaphylaxis.
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PMID:Attenuation of rat conjunctival response by repeated hapten applications. 314 Nov 14

Derivatives of D-luciferin, D-luciferin methyl ester, D-luciferin O-sulfate, D-luciferin O-phosphate, D-luciferyl-L-N alpha-arginine and D-luciferyl-L-phenylalanine were used as highly sensitive substrates for carboxylic esterase, arylsulfatase, alkaline phosphatase and carboxypeptidases A, B and N. Enzymatic cleavage of the compounds by enzymes leading to the release of D-luciferin was demonstrated. Kinetic constants have been determined for D-luciferin methyl ester and carboxylic esterase, for D-luciferin O-sulfate and arylsulfatase, for D-luciferin O-phosphate and alkaline phosphatase, for D-luciferyl-L-phenylalanine and carboxypeptidase A, and for carboxypeptidases B and N and D-luciferyl-L-N alpha-arginine. All compounds proved to be highly sensitive substrates for the respective enzymes, permitting a limit of detection for enzymes between 10 and 500 fg per assay.
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PMID:A new type of ultrasensitive bioluminogenic enzyme substrates. I. Enzyme substrates with D-luciferin as leaving group. 316 46

Mast cells isolated from the peritoneal fluid of Wistar rats were purified by centrifugation on Percoll gradient with a yield of 2x10(6) cells/ml. Cell morphology was well preserved as shown by light and electron microscopy. The mast cells capacity to bind histamine was assayed using either [3H]-histamine or histamine-ferritin conjugate as electron-opaque probe for electron microscopic examination. The [3H]-histamine binding performed at 4 degrees C in Ca2+-free phosphate-buffered saline pH 7.3 completed within 30 min was found to be specific, with an IC50 value of 0.72 +/- 0.23 nM. The data analyses by Scatchard and Hill's representations showed a KD of 0.60 +/- 0.24 nM and Bmax of 4.9 +/- 1.2 pM/10(6) cells suggesting that on mast cells the histamine receptors are restricted to the plasma membrane. According to Hill's analysis neither positive nor negative cooperativity (n = 1.06) appeared to be involved in the specific histamine-receptor binding. Competition experiments with 4-methylhistamine and SK&F 93479, revealed that mast cells express H2-histamine receptors. At electron microscopic level, the histamine-ferritin conjugate interstitially injected in the hamster cheek pouch was localized on the mast cell membrane.
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PMID:Histamine receptor on mast cells. 325 80

Progressively increasing doses of aspirin (acetylsalicylic acid--ASA) were tolerated by 14 out of 15 patients with confirmed aspirin-sensitive urticaria and in 7 out of 9 patients with aspirin-sensitive asthma. Blood levels of histamine and prostaglandin (PG) F2 alpha were significantly raised in these patients before ASA administration. PGF2 alpha levels fell to within the normal range after challenge doses of ASA which were sufficient to cause symptoms. Skin prick testing with histamine and codeine phosphate did not show evidence of abnormal tissue reactivity or mast cell reactivity. A wider spectrum of mediators will need to be considered if the mechanism of symptom production is to be understood.
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PMID:Clinical and biochemical aspects of "aspirin-sensitivity". 347 39

Derivatives of luciferin, D-luciferin methyl ester, D-luciferyl-L-phenylalanine, D-luciferyl-L-N alpha-arginine, D-luciferin-O-sulphate and D-luciferin-O-phosphate, were synthesized for use as highly sensitive substrates for enzyme assays. The luciferin derivatives were characterized by ultraviolet and fluorescence spectrophotometry, by amino acid analysis and by fast atom bombardement mass spectrometry. Enzymatic cleavage of the compounds by enzymes leading to the release of D-luciferin was demonstrated. Kinetic constants were determined for the following enzyme/substrate pairs: D-luciferin methyl ester/carboxylic esterase, D-luciferyl-L-phenylalanine/carboxypeptidase A, D-luciferyl-L-N alpha-arginine/carboxypeptidase B, D-luciferin-O-sulphate/arylsulphatase, D-luciferin-O-phosphate/alkaline phosphatase. All compounds proved to be acceptable substrates for the respective enzymes, D-luciferin-O-phosphate being accompanied by an especially high turnover number (kcat = 1010 s-1) with alkaline phosphatase.
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PMID:Synthesis and characterization of luciferin derivatives for use in bioluminescence enhanced enzyme immunoassays. New ultrasensitive detection systems for enzyme immunoassays, I. 354 62

We have compared the digestion of bradykinin, lysyl bradykinin, and kinin degradation products by carboxypeptidases N, B and A (CPN, CPB and CPA). Carboxypeptidase N removed the C-terminal arginine from bradykinin or lysyl bradykinin to leave the des-Arg derivative of each, and no further degradation occurred regardless of enzyme concentration or time of incubation. However, both CPB and CPA degraded the des-Arg derivatives to remove the C-terminal phenylalanine. The inhibitory effect of phosphate ions upon this activity of CPB (but not CPA) suggests that CPA may be responsible for the formation of free phenylalanine seen upon degradation of kinins in plasma or serum. However, angiotensin converting enzyme degraded des-Arg9-bradykinin in plasma or serum prior to such Phe removal to yield the pentapeptide Arg-Pro-Pro-Gly-Phe and the tripeptide Ser-Pro-Phe. We demonstrated that CPB degraded Arg-Pro-Pro-Gly-Phe but not Ser-Pro-Phe; this reaction was also inhibited by phosphate ions. Carboxypeptidase A, on the other hand, liberated Phe from both peptides in phosphate-buffered saline and accounted, at least in part, for the free phenylalanine detected. Carboxypeptidase N did not digest the aforementioned pentapeptide or tripeptide. It is clear that carboxypeptidase B and carboxypeptidase A had overlapping activities, depending upon the substrate tested, and were distinguished by the effects of different ionic environments. We further suggest a role for carboxypeptidases other than CPN in the degradation of kinins in human plasma or serum.
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PMID:Studies of the digestion of bradykinin, lysyl bradykinin, and kinin-degradation products by carboxypeptidases A, B, and N. 371 39


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