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)

The intestine is richly populated with lymphoid tissue capable of initiating and effecting a wide variety of immunologic reactions. These reactions have consequences not only for the gut itself but for the body in general, and have established the importance of the gut as an immunologic organ. Among the outer and inner surfaces of our body, the 200 to 300 m2 of the gut contrast with the 2 m2 of the skin, and the 80 m2 of the lung. At the inner surface of the intestine, our organism contacts intimately bacteria, parasites, enzymes, toxins, a wide variety of dietary substances and their breakdown products. The essential barrier against the permanent antigenic burden is the mucosa. Its integrity depends on the continual replication, maturation, and metabolism of its constituents. Additional defense functions are exerted by the mucus, lysozyme, phagocytes, other cells, humoral factors and biological response modifiers involved in inflammatory and immune reactions. Some of these factors are being produced very close to the surface at which they act. The sum of the mechanical, humoral, cellular, immunologic and non-immunologic defense factors of the intestinal mucosa constitutes the mucosal block. However, the block is not complete. Rather, a continuous antigenic uptake through the epithelial layer takes place. The specialized structures of Peyer's patches, solitary lymph follicles, appendix vermiformis and their associated epithelium allow a controlled antigen uptake (sampling). Because of the heavy antigenic load, the intestine can be described as the most important immunologic contact organ of our body. The antigens may give rise to local and systemic immune reactions with antibody production, or the suppression of systemic immunologic responses to ingested antigens ("oral tolerance").
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PMID:Immunologic structures and functions of the gut. 266 24

1. Non-pathogenic microorganisms, known as mycetocyte symbionts, are located in specialized 'mycetocyte' cells of many insects that feed on nutritionally unbalanced or poor diets. The insects include cockroaches, Cimicidae and Lygaeidae (Heteroptera), the Homoptera, Anoplura, the Diptera Pupiparia, some formicine ants and many beetles. 2. Most mycetocyte symbionts are prokaryotes and a great diversity of forms has been described. None has been cultured in vitro and their taxonomic position is obscure. Yeasts have been reported in Cerambycidae and Anobiidae (Coleoptera) and a few planthoppers. They are culturable and those in anobiids have been assigned to the genus Torulopsis. 3. The mycetocyte cells may be associated with the gut, lie free in the abdominal haemocoel or be embedded in the fat body of the insect. The mycetocytes are large polyploid cells which rarely divide and the symbionts are restricted to their cytoplasm. 4. The mycetocyte symbionts are transmitted maternally from one insect generation to the next. In many beetles (Anobiidae, Cerambycidae, Chrysomelidae and cleonine Curculionidae), the microoganisms are smeared onto the eggs and consumed by the hatching larvae. In other insects, they are transferred from mycetocytes to oocytes in the ovary, a process known as transovarial transmission. The details of transmission in the different insect groups vary with the age of the mother (adult, larva or embryo) at which symbiont transfer to the ovary is initiated; whether isolated symbionts or intact mycetocytes are transferred; and the site of entry of symbionts to the egg (anterior, posterior or apolar). 5. Within an individual insect, the biomass of symbionts varies in a regular fashion with age, weight and sex of the insect. Suppression of symbiont growth rate and lysis of 'excess' microorganisms may contribute to the regulation of symbionts (including freshly-isolated preparations of unculturable forms) are used to investigate interactions between the partners. However, some methods to obtain aposymbiotic insects (e.g. antibiotics and lysozyme) deleteriously affect certain insects and aposymbionts may differ from the symbiont-containing stocks from which they were derived. 7. The mycetocyte symbionts have been proposed to synthesize various nutrients required by the insect. The symbionts of beetles and haematophagous insects may provide B vitamins and those in cockroaches and the Homoptera essential amino acids. The role of symbionts in the sterol nutrition of insects is equivocal. 8. Mycetocyte symbionts may have evolved from gut symbionts or guest microorganisms. The association is monophyletic in cockroaches but polyphyletic in many groups, including the sucking lice, beetles and scale insects.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Mycetocyte symbiosis in insects. 269 62

Although it has generally been accepted that the main structural component of mucus secretions is the high molecular weight glycoprotein it has now been established that other macromolecules are co-secreted. For example, lysozyme, lactoferrin and albumin are known to be secreted by the serous cells within the sub-mucosal respiratory glands: significantly the albumin is synthesised within the cell and is not derived from serum. The various cells within the gland respond differently to agonists and since goblet cells, apart from when they are in the crypts within the gastro-intestinal tract, do not appear to be innervated, they cannot respond to any agonist as yet identified. It is therefore probable that the changes which occur during disease may result from changes in the sensitivity of a particular cell type to an agonist as this can markedly affect the type of secretion that is produced. Since the products of the serous cell form part of the natural defence system then the reduction in their number which is observed in chronic obstructive airways disease could also be significant in the disease process. Within the gastro-intestinal tract, it has now been established that substances which reduce the mucus structure can produce damage to the underlying membrane. The endogenous surfactants produced in bile are good examples and co-secretion of phosphatidylcholine provides a defence against self-digestion within the gut by the formation of mixed micelles. The importance of the mucus layer in the access of drug molecules to the absorbing epithelium has also been identified. The diffusion of water molecules is hindered even at concentrations below the gelling point (approximately 10-20 mg ml-1) and above this concentration a precipitate fall in diffusion coefficient is followed by a levelling off. This pattern is followed by low molecular weight drug molecules and a reasonable correlation between drug absorption and binding to mucus glycoproteins can be demonstrated. The agents which have been claimed to affect the quality and quantity of mucus secreted by the respiratory epithelium during conditions like chronic obstructive airways disease have been poorly understood. Recent studies have shown that compounds like bromhexine and S-carboxymethylcysteine can block the activity of mucus secretagogues in the rat. Furthermore, it has also been demonstrated that such compounds can prevent the inflammatory response to cigarette smoke. However, their activity is not restricted to the respiratory epithelium and the cervical mucus barrier has also been shown to be compromised following systemic administration.
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PMID:Drug-mucus actions and interactions. 270 76

The response of luminous bacterial cultures to conditions encountered in the fish gut such as neutral pH, the presence of bile salts, gastric juice and lysozyme was examined. The organisms preferred neutral pH. Bile salts did not inhibit their growth. Neither lysozyme nor gastric juice affected their growth and viability to any extent. In the light of these findings, the adaptability of luminous bacteria to conditions existing in the gut of fish was discussed.
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PMID:Response of enteric luminous bacteria to environmental conditions in the gut of the fish. 275 45

We have used immunoperoxidase techniques to characterise the Peyer's patches in human terminal ileum. The mantle zones of the B cell follicles in human Peyer's patches were surrounded by B cells which did not express surface IgD but which mostly expressed surface immunoglobulin of the IgM and/or IgA1 isotype. Few cells expressing surface IgG or IgA2 were detected. Cells with cytoplasmic immunoglobulin of all isotypes except IgD were present in the dome regions of the Peyer's patches as well as in the lamina propria. There was little evidence of traffic of immunoglobulin synthesising cells across the high endothelial venules. T cells were seen to surround the lymphoid follicles. They were most concentrated on the serosal aspect around the high endothelial venules. Cells with macrophage-like morphology were present in both the lamina propria and the dome region of the follicles; those in the lamina propria containing lysozyme and those in the dome region S100 protein. The results are discussed in relation to the generation and dissemination of antibody producing cells in human gut.
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PMID:Human Peyer's patches: an immunohistochemical study. 351 87

A total of 49 gastric tubular adenomas and 6 tubular adenomas with foci of adenocarcinoma from surgically resected stomachs were examined histologically and immunohistochemically for gut peptide hormones, serotonin, carcinoembryonic antigen (CEA), secretory component (SC), and lysozyme. A variety of endocrine cells were detected in tubular adenoma with mild to moderate atypia. Both the frequency and distribution density were highest for serotonin-containing EC cells, often showing hyperplasia, followed by glicentin-containing L cells, somatostatin-containing D cells and motilin-containing Mo cells in the order given. Adenoma cells with SC immunoreactivity were more dominant than those with CEA immunoreactivity. In tubular adenoma with severe atypia, endocrine cells were markedly decreased, whereas adenoma cells with CEA immunoreactivity were increased. The distribution density of lysozyme-containing cells in tubular adenoma of the intermediate zone and fundus was significantly higher than that of the antrum. In the subjacent mucosa of the adenoma, L cells and SC-positive epithelial cells were detected in 24 and 33 cases, respectively. These findings suggest that gastric tubular adenoma develops from intestinal metaplasia. In addition, gastric tubular adenoma showed a tendency to lose various intestinal markers with increase of histologic atypicality.
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PMID:Tubular adenoma of the human stomach. An immunohistochemical analysis of gut hormones, serotonin, carcinoembryonic antigen, secretory component, and lysozyme. 353 Apr 27

Lactobacilli can belong to the gut flora or to the flora associating with gastrointestinal epithelial surfaces. They play an important role within the microbial defense mechanisms taking part in the colonization resistance and in the decontamination of the host. Lactobacilli affect the immune response. They accelerate the revival of the small intestinal epithelial cells. Those strains of lactobacilli with distinct antagonistic properties with lysozyme activity and resistance against lysozyme often develop a compact glycocalyx. They are endowed with a high adhesion capacity. The intestinal lactoflora consists of several species with different defense properties.
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PMID:[The defense function of the digestive tract lactoflora]. 365 15

We examined the infiltration in chronic superficial gastritis immunohistochemically on the contents of IgA-, IgG- and IgM-containing plasma cells and on lysozyme and compared the results on the one hand with those of histologically normal gastric mucosa and on the other side with those of the inflammation at the ulcus border. Not as immunology-related reactions of the gut, one can see the chronic superficial gastritis as a stronger and topographically different variant of the normal reaction of the stomach. It shows the flowing threshold between physiological and accentuated defense and pathological exaggeration.
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PMID:[Surface gastritis. Immunoglobulins and lysozyme. The border zone between physiology and pathology]. 390 45

Lysozyme is a bacteriocidal enzyme which is a major stable secretory product of mononuclear phagocytes, including hepatic sinusoidal macrophages (HSM), and serves as a good marker for these cells. Patients with alcoholic liver disease (ALD) have decreased HSM function which is reflected in reduced clearance of microorganisms and endotoxin derived from the gut. The HSM population in 54 liver biopsies from patients with ALD was studied using immunoperoxidase staining of lysozyme and was compared with 15 histologically normal controls. In both groups lysozyme positive HSM were more numerous in periportal than perivenous parenchyma. In each zone there were significantly fewer positive HSM in cases of ALD than in controls, in alcoholic hepatitis than in ALD without hepatitis, and in cirrhosis than in ALD without cirrhosis. These findings suggest a decreased population of functionally active HSM in ALD which correlates with severity of liver damage. This might be due to decreased lysozyme content of the entire HSM population or to the existence of two populations, one positive and one negative for lysozyme. The observed decrease in HSM function explains many of the phenomena observed in ALD.
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PMID:Hepatic sinusoidal macrophages in alcoholic liver disease. 390 65

The sensitivity to sodium lauryl sulfate (SLS) of Shigella flexneri and Escherichia coli is determined by at least three genes. One site is located near the lactose operon, and two loci are cotransducible with the arabinose operon. Calcium ions protect against SLS lysis. One gene is concerned with the relative ability of the bacterium to retain calcium against such chelating agents as ethylenediaminetetraacetic acid or phosphate buffer. This was first observed in a mutation from virulence to avirulence in S. flexneri with a concomitant loss of ability to penetrate the intestinal epithelium. The avirulent strain is far less sensitive to lysis by SLS in the presence of phosphate buffer than its virulent parent. The avirulent strain is also less sensitive to lysozyme and ethylenediaminetetraacetic acid. E. coli K-12 is much more sensitive to SLS than both of these Shigella strains. An E. coli-S. flexneri hybrid, which is unable to survive well in the gut and thus only produces an abortive infection, has inherited this extreme sensitivity to SLS.
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PMID:Mechanisms and genetics of resistance to sodium lauryl sulfate in strains of Shigella and Escherichia coli. 500 97


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