Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.17 (lysozyme)
 21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mechanisms were studied that might explain the attachment and damage to Candida albicans pseudohyphae by neutrophils in the absence of serum. Attachment of neutrophils to pseudo hyphae was inhibited by Candida mannans (1-10 mg/ml), but not by mannose, dextran, chitin, conconavalin A, or highly charged polyamino acids. Contact was also inhibited by pretreatment of Candida before incubation with neutrophils with chymotrypsin, but not trypsin or several inhibitors of proteases. Similar results were obtained with pretreatment of neutrophils, except that trypsin was inhibitory. When pseudohyphae were killed with ultraviolet light, proteinpolysaccharide complexes of mol wt <10,000 were released which appeared to bind to the surfaces of neutrophils and inhibit contact between neutrophils and Candida, as well as other fungi. Damage to Candida by neutrophils was inhibited by agents known to act on neutrophil oxidative microbicidal mechanisms, including sodium cyanide, sodium azide, catalase, superoxide dismutase, and 1, 4 diazobicyclo (2, 2, 2) octane, a singlet oxygen quencher. Neutrophils from a patient with chronic granulomatous disease did not damage Candida at all. However, the hydroxyl radical scavengers mannitol and benzoate were not inhibitory. Cationic proteins and lactoferrin also did not appear to play a major role in this system. Low concentrations of lysozyme which did not damage Candida in isotonic buffer solutions damaged pseudohyphae in distilled water. Isolated neutrophil granules damaged pseudohyphae only with added hydrogen peroxide and halide, and damage occurred only with granule fractions known to contain myeloperoxidase. These findings suggest that neutrophils recognized a molecule on the Candida surface which has a chymotrypsin sensitive protein component, and which may be liberated from the cell surface upon death of organism. The neutrophil receptors for Candida appear to be sensitive to trypsin and chymotrypsin. Damage to Candida by neutrophils occurred primarily by oxidative mechanisms, including the production of superoxide and hydrogen peroxide interacting with myeloperoxidase and halide, as well as singlet oxygen, but did not appear to involve hydroxyl radical. Lysozyme might have an accessory role, under some conditions.
 ...
PMID:Mechanisms of attachment of neutrophils to Candida albicans pseudohyphae in the absence of serum, and of subsequent damage to pseudohyphae by microbicidal processes of neutrophils in vitro. 34 Apr 71

Polymorphonuclear leukocytes (PMNs) are one of the main sources of enzymes responsible for tissue damage in inflammatory processes. These enzymes are stored in two types of cytoplasmic granules. Azurophil granules contain lysosomal hydrolases, neutral serine proteinases, and bactericidal elements (myeloperoxidase and lysozyme). Specific granules contain collagenase, lysozyme and lactoferrin but lack lysosomal hydrolases. PMNs store all four classes of tissue proteinases, carboxyl, thiol and serine proteinases in the azurophil granules, and metallo proteinases in the specific granules. Three serine proteinases have been identified, elastase, cathepsin G and a third enzyme, which together account for a large proportion of the protein of the azurophil granules. In the course of phagocytic events, all these enzymes are released extracellularly. The neutral proteinases degrade proteoglycans and collagen. In vitro, they stimulate B-lymphocytes, which suggests that they may have immuno-potentiating activity when they are released at sites of chronic inflammation.
 ...
PMID:The polymorphonuclear leukocyte. 34 82

The role of ascorbic acid is reviewed with regard to antimicrobial activity, interferon production, and humoral and cellular immune responses. Ascorbic acid appears to play a role in a number of neutrophil functions including increased chemotaxis, increased particulate ingestion, enhanced lysozyme-mediated non-oxidative killing, protection against the toxic effects of superoxide anion radical, inhibition of the halide-peroxide-myeloperoxidase system without a pronounced bactericidal effect, and stimulation of the hexose monophosphate shunt.
 ...
PMID:Ascorbic acid, neutrophil function, and the immune response. 35 20

Proteins from human polymorphonuclear leukocyte granules were extracted with 0.2 M acetate, pH 4.0, and fractionated by Sephadex G-100 column chromatography. The fractions demonstrated selective bactericidal action against a deep rough cell wall mutant of Escherichia coli O111:B4 with rough lipopolysacharide and cell wall mutants of Salmonella typhimurium LT-2 with lipoplysacharide of Ra, Rc, Rd1, Rd2, and Re types. Smooth parent strains were most resistant to the bactericidal action. Fractions with greatest activity for the mutants were from valley regions (regions of low protein concentration) between three high protein peaks comprising myeloperoxidase, protease, and lysozyme, respectively. Susceptibility of the mutants to bactericidal action increased as sugar residues decreased in lipopolysaccharide. Gram-positive bacteria were susceptible to different fractions than were the gram-negative bacteria.
 ...
PMID:Bactericidal activity of fractionated granule contents from human polymorphonuclear leukocytes. 37 30

High titer, monospecific antibodies to human granulocyte myeloperoxidase, cathepsin G, elastase, lysozyme, and lactoferrin were conjugated with fluorescein and rhodamine and used for immunofluorescent staining of mature neutrophils obtained from 25 patients with acute and chronic leukemia. In 11 (44%) of the patients, two populations of mature neutrophils were detected. The abnormal cells were identified by complete deficiency of one or more markers and constituted 10%-100% of the total number of neutrophils. This immunocytochemical approach may permit recognition of mature cells derived from leukemic clones, and serial determinations of the ratio of normal to abnormal cells may be useful in the management of patients with leukemia.
 ...
PMID:Immunocytochemical identification of abnormal polymorphonuclear neutrophils in patients with leukemia. 40 Aug 91

Enzymaticaly homogeneous fractions of lymphocytes, monocytes, and neutrophils were isolated by zonal centrifugation from peripheral blood of a patient with hairy cell leukemia, or leukemic reticuloendotheliosis, LRE,(with leukopenia, neutropenia, lymphocytosis, and massive splenomegaly). To detect enzymatic deficiencies, the cells were analyzed quantitatively for six leukocytic enzymes on three occasions: 1) before splenectomy, 2) 5 days after splenectomy, and 3) 6 weeks after splenectomy. Before splenectomy, the patient's cells showed moderate deficiency of beta-glucuronidase in lymphocytes and monocytes; server to modorate deficiency of lysozyme and myeloperoxidase in monocytes and granulocytes; and complete absence of neutral protease and alkaline phosphates in neutrophils. Full restoration of neutral protease and a three-fold rise in alkaline phosphatase activities occurred in the patient's neutrophils 5 days after splenectomy. Lysozyme and myeloperoxidase returned to normal in both monocytes and neutrophils of the patient. Six weeks following splenectomy, the alkaline phosphatase activity again disappeared from patient's neutrophils, although neutral protease remained normal. The patient's lymphocytes were unresponsive to PHA and PW mitogen before splenectomy but became responsive 6 weeks postoperatively. Monocytic transfomation into macrophges was supressed before and after splenectomy. The findings indicate that developmenally, in lymphocytic leukemia, a biochemical defect involves the patient's monocytes and neutrophils much more severely than it affects the leukemic lymphocytes. Functionally, the results partly explain the susceptibility of LRE patients to microbial infections.
 ...
PMID:Absence of neutral protease and alkaline phosphatase in neutrophils of a case of hairy cell leukemia. 43 13

The effects of a highly-purified, potently bactericidal fraction from rabbit polymorphonuclear leukocytes on the envelope of Escherichia coli (W) have been examined. This leukocyte fraction has equally enriched bactericidal, permeability-increasing and phospholipase A2 activities, and is essentially devoid of lysozyme, myeloperoxidase and protease activities (Weiss, J., Franson, R.C., Beckerdite, S., Schmeidler, K. and Elsbach, P. (1975) J. Clin. Invest. 55, 33-42). Rapid killing of E. coli by this fraction is accompanied by two almost immediate alterations in the bacterial envelope: (1) a discrete increase in envelope permeability (measured by inhibition of bacterial leucine incorporation by normally impermeant actinomycin D), and, (2) hydrolysis of 14C-labeled fatty acid-prelabeled E. coli phospholipids. Both envelope effects are promptly reversed during further incubation at 37 degrees C, But not at 0 degrees C, with 40 mM Mg2+. Reversal is also produced by Ca2+ (40 mM) and trypsin (200 mug/ml), but 200 mM K+ causes only partial recovery and Na+ and hyperosmolar sucrose are ineffective. Upon addition of Mg2+, phospholipid degradation ceases abruptly and the labeled products of hydrolysis (free fatty acids and lysocompounds) disappear with a corresponding reaccumulation of radioactive diacylphosphatides. The time course of resynthesis of phospholipids coincides with that of restoration of the permeability barrier. Higher concentrations of the leukocyte fraction and prolonged incubation increase both the extent of phospholipid degradation and the time required for reversal of both envelope effects. These findings suggest that both the initiation of the increased permeability and its reversal are linked to respectively the breakdown and resynthesis of major E. coli membrane phospholipids, and thus depend on the fact that the biochemical apparatus of E. coli remains capable of biosynthesis despite loss of viability. Treatment of E. coli, exposed to the leukocyte fraction, with albumin results in extracellular sequestration of the products of hydrolysis and also restores the permeability barrier to actinomycin D, suggesting that the accumulation of lytic products of lipid hydrolysis within the bacterial envelope, rather than the loss of phospholipids per se, causes increased permeability Whereas the effects on the envelope are reversible as long as 2 h after nearly complete loss of ability to multiply by E. coli, the effect on bacterial multiplication is irreversible within 5 min.
 ...
PMID:Reversible envelope effects during and after killing of Escherichia coli w by a highly-purified rabbit polymorpho-nuclear leukocyte fraction. 77 27

Reccurrent abnormalities of polymorphonuclear leukocyte and monocyte bactericidal activity were demonstrated in a patient with sarcoidosis. Defective function occurred during hypercalcemia complicating recovery from Listeria meningitis, and during separate, unrelated episodes of erythema nodosum, staphylococcal cellulitis, and pneumococcal pneumonia. Leukocyte morphology, oxidative metabolism, degranulation, and content of myeloperoxidase and lysozyme were normal, but low leukocyte alkaline phosphatase activity was demonstrable on one occasion. Despite defective bactericidal function of monocytes, the patient's macrophages killed bacteria normally. The relationship between an intermittent leukocyte bactericidal defect and sarcoidosis is unclear; however, further studies of leukocyte function in sarcoidosis patients with opportunistic infection are indicated.
 ...
PMID:Intermittent neutrophil-monocyte bactericidal defects in a patient with sarcoidosis. 80 91

The success of colchicine therapy in the management of familial Mediterranean fever has provided new direction to investigations into the pathogenesis of this disease. Examination of HLA antigen frequencies in 53 patients with familial Mediterranean fever and appropriate controls, as well as various immunologic studies have yielded no significant differences. However, B lymphocyte typing and assays for immune complexes, lymphokines and prostaglandins may be of potential interest. Preliminary studies indicate that leukocytes of patients with familial Mediterranean fever release increased amounts of lysozyme (P<0.01), when subjected to high temperatures, and of both lysozyme and myeloperoxidase at low osmotic concentrations. The known and potential effects of colchicine on leukocyte and cellular metabolism, and the current status of colchicine prophylaxis are reviewed. In patients receiving an optimum colchicine dose of 1.5 to 1.8 mg per day, side effects have been minimal and the frequency of attacks has been decreased significantly.
 ...
PMID:Familial Mediterranean fever. Recent advances in pathogenesis and management. 87 70

Microorganisms ingested by PMNs are exposed to a variety of antimicrobial systems. Together they comprise a formidable armamentarium, and few organisms survive. The predominant antimicrobial system would be expected to vary with the species, the availability of oxygen and the type of microorganism ingested. There is considerable evidence that the MPO-mediated antimicrobial system plays an important role in the destruction of certain microorganisms in most species; chicken heterophils, however, do not contain MPO,40 and some microorganisms are resistant to this system due to the nature of their cell wall material.146 Further, microbial catalase may offer some protection. The granulocytes of some species (e.g., rabbit, chicken) are rich in cationic proteins and these agents may play a particularly important role in these cells. Granular cationic proteins are less plentiful in human cells.111 Organisms vary in their susceptibility to lysozyme and this enzyme is absent from bovine leukocytes.113 It is probable that the total microbicidal potential of the leukocyte is in excess of its needs under most circumstances. This "overkill" capacity is a reflection of both the level of activity of individual systems and their variety. Particular organisms are susceptible to more than one antimicrobial system and thus may be effectively handled by back-up systems when one is absent. Thus, an organism normally killed by the peroxidase system may be handled less efficiently but adequately when MPO is absent by other oxygen-dependent antimicrobial systems. When a defect in oxidative metabolixm is present as in CGD, both MPO-catalyzed and nonenzymatic oxygen-dependent systems are absent. The ingested organism can, in some instances, supply the needed product of oxidative metabolism (i.e., H2O2); in other instances, oxygen-independent antimicrobial systems are adequate to prevent microbial growth. However, in yet other instances, the organisms survive and multiply and severe infection results.
 ...
PMID:Antimicrobial mechanisms in neutrophilic polymorphonuclear leukocytes. 111 38


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>