Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

After isolation of the hamster small intestine, the effects of a continuous infusion of cholecystokinin-pancreozymin (CCK-PZ) are studied. Several enzymic activities are measured in the intestinal lumen and compared with the level found in the intestinal homogenate. During CCK-PZ infusion we observed a direct stimulation of Paneth cells associated with an increase of lysozyme activity. Furthermore this work confirms the stimulating effect of CCK-PZ on alkaline phosphatase and amino-peptidase. Maltase and sucrase levels were unaffected. The liberation of the hydrolase of the brush border in the intestinal lumen is negligible and cannot be considered as a true secretion. Only granule content of Paneth cells is actually secreted. However, biochemical data, corroborated by morphological results, suggest that Paneth cell secretion could in part be absorbed on the outer surface of the brush border.
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PMID:Comparative effects of CCK-PZ on certain intestinal hydrolases in the mucosa and in the luminal content of the hamster jejuno-ileum. 39 57

Hamster intestinal hydrolase activities were studied after pancreatic duct ligation for periods of 5, 7, 10, 15 and 30 days. From the 7th to the 10th day, maltase and sucrase were significantly increased in the jejunoileum. Higher levels were observed on day 7 in the duodenum for all the brush-border enzyme activities (maltase, sucrase, aminopeptidase, alkaline phosphatase). Intestinal lysozyme significantly increased from the 5th to the 15th day with a maximal level at the 7th day. The increased levels of brush-border enzymes observed here are not in accordance with our description of villous atrophy after pancreatic duct ligation in the hamster. On the other hand, the important increase in lysozyme activity is in good agreement with hypertrophy and hyperplasia of the Paneth cells which we observed during our morphological study. The morphological and biochemical findings on hamster small intestine confirm the effects of exocrine pancreatic secretion both on differentiation and on enzymatic levels of the mucosa. Besides, this experiment agrees with the direct desorbing action of the pancreatic juice on the brush border and suggests another hypothetical mechanism, still worth being investigated, to explain increased brush-border activities in the duodenum and increased levels of lysozyme in the jejunoileum.
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PMID:Effect of pancreatic duct ligation on the hamster intestinal mucosa. Variation of several hydrolases. 722 72

Samples of whole saliva and dental plaque were collected from initially 10-year old subjects who participated in a 40-month cohort study investigating the effect of chewing gum usage on caries rates. The subjects represented nine cohorts of which one did not receive gum, while in eight cohorts the subjects received gum containing either xylitol, sorbitol, their mixtures, or sucrose as bulk sweeteners, the maximum sweetener consumption in the form of gums being up to 10.7 g/day, used in 3-5 daily chewing episodes. Gum usage had no significant effect on the levels of salivary protein, IgA, alpha-amylase, peroxidase, lysozyme, SCN and buffer capacity. At the endpoint, the group that received 100% xylitol pellet-shaped gum five times/day, had significantly lower levels of sucrase (p <0.05) and free sialic acid (p < 0.001) in whole saliva than at baseline. This group showed significantly (p <0.05) smaller plaque index scores at two cross-sectional measurements, and exhibited the lowest log(10) counts of salivary lactobacilli at endpoint than most other groups. The salivary levels of peptidase(s) (oligopeptidase B-like enzymes) hydrolyzing N-alpha-benzoyl-DL-arginyl-p-nitroaniline were significantly (p<0.05) or almost significantly lower in groups which received 100% xylitol pellet gums. All groups exhibited obviously an aging-related increase of salivary mutans streptococcus scores, except the above xylitol group in which the mean scores did not change.
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PMID:Properties of whole saliva and dental plaque in relation to 40-month consumption of chewing gums containing xylitol, sorbitol of sucrose. 886 27

Proliferation, differentiation, and cell death were studied in small intestinal and colonic epithelia of rats after treatment with methotrexate. Days 1-2 after treatment were characterized by decreased proliferation, increased apoptosis, and decreased numbers and depths of small intestinal crypts in a proximal-to-distal decreasing gradient along the small intestine. The remaining crypt epithelium appeared flattened, except for Paneth cells, in which lysozyme protein and mRNA expression was increased. Regeneration through increased proliferation during days 3-4 coincided with villus atrophy, showing decreased numbers of villus enterocytes and decreased expression of the enterocyte-specific genes sucrase-isomaltase and carbamoyl phosphate synthase I. Remarkably, goblet cells were spared at villus tips and remained functional, displaying Muc2 and trefoil factor 3 expression. On days 8-10, all parameters had returned to normal in the whole small intestine. No methotrexate-induced changes were seen in epithelial morphology, proliferation, apoptosis, Muc2, and TFF3 immunostaining in the colon. The observed small intestinal sparing of Paneth cells and goblet cells following exposure to methotrexate is likely to contribute to epithelial defense during increased vulnerability of the intestinal epithelium.
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PMID:Selective sparing of goblet cells and paneth cells in the intestine of methotrexate-treated rats. 1105 2

The crypt and villus epithelium associated with Peyer's patches (PPs) is largely spared from methotrexate (MTX)-induced damage, compared with the non-patch (NP) epithelium. To assess the mechanism(s) preventing damage to the PP epithelium after MTX treatment, epithelial proliferation, apoptosis, and cell functions were studied in a rat-MTX model. Small intestinal segments containing PPs were excised after MTX treatment. Epithelial proliferation and apoptosis were assessed by detection of incorporated BrdU and cleaved caspase-3, respectively. Epithelial functions were determined by the expression of cell type-specific gene products at mRNA and protein level. Before and after MTX treatment, the number of BrdU-positive cells was higher in PP crypts than in NP crypts. BrdU incorporation was diminished in NP crypts, while in PP crypts incorporation was hardly affected. In PP and NP crypts, similar and increased levels of cleaved caspase-3-positive cells were observed after MTX. The enterocyte markers, sucrase-isomaltase, sodium-glucose co-transporter 1, glucose transporters 2 and 5, and intestinal and liver fatty acid binding protein, were down-regulated after MTX in NP epithelium but not in PP epithelium. In contrast, expression of the goblet cell markers, Muc2 and trefoil factor 3, and the Paneth cell marker, lysozyme, was maintained after MTX in both PP and NP epithelium. In conclusion, as MTX-induced apoptosis was similar in PP and NP crypts, the protection of the PP epithelium seems to be based on differences in the regulation of epithelial proliferation. Enterocyte function in the PP epithelium was unaffected by MTX treatment. Goblet and Paneth cell function was maintained in both NP and PP epithelium.
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PMID:Protection of the Peyer's patch-associated crypt and villus epithelium against methotrexate-induced damage is based on its distinct regulation of proliferation. 1221 64

The rapidly dividing small intestinal epithelium is very sensitive to the cytostatic drug methotrexate. We investigated the regulation of epithelial gene expression in rat jejunum during methotrexate-induced damage and regeneration. Ten differentiation markers were localized on tissue sections and quantified at mRNA and protein levels relative to control levels. We analyzed correlations in temporal expression patterns between markers. mRNA expression of enterocyte and goblet cell markers decreased significantly during damage for a specific period. Of these, sucrase-isomaltase (-62%) and CPS (-82%) were correlated. Correlations were also found between lactase (-76%) and SGLT1 (-77%) and between I-FABP (-52%) and L-FABP (-45%). Decreases in GLUT5 (-53%), MUC2 (-43%), and TFF3 (-54%) mRNAs occurred independently of any of the other markers. In contrast, lysozyme mRNA present in Paneth cells increased (+76%). At the protein level, qualitative and quantitative changes were in agreement with mRNA expression, except for Muc2 (+115%) and TFF3 (+81%), which increased significantly during damage, following independent patterns. During regeneration, expression of each marker returned to control levels. The enhanced expression of cytoprotective molecules (Muc2, TFF3, lysozyme) during damage represents maintenance of goblet cell and Paneth cell functions, most likely to protect the epithelium. Decreased expression of enterocyte-specific markers represents decreased enterocyte function, of which fatty acid transporters were least affected.
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PMID:Specific responses in rat small intestinal epithelial mRNA expression and protein levels during chemotherapeutic damage and regeneration. 1241 19

During organogenesis, the intestinal tract progressively acquires a functional regionalization along the antero-posterior axis. Positional information needed for enterocytes has been studied, but the mechanisms that control Paneth and endocrine cell differentiation are poorly understood. We have used a model of endoderm/mesenchyme cross-associations to evaluate the respective roles of endoderm and mesenchyme in the cytodifferentiation of these epithelial cells. Heterotopic cross-associations comprising endoderm and mesenchyme from the presumptive proximal jejunum and colon were developed as xenografts in nude mice. Our results show that endoderm from the presumptive proximal jejunum when associated with colonic mesenchyme generate small intestinal enterocytes. Interestingly, no lysozyme-producing cells were generated. On the other hand, associations comprising colon endoderm and jejunal mesenchyme showed heterodifferentiation with typical small intestinal morphology with sucrase-isomaltase expression and Paneth cell differentiation. Heterotopic associations developed enteroendocrine cell patterns according to the normal fate of the endodermal moiety. As enteroendocrine cell commitment seems to occur before the other intestinal cell types, we cannot exclude a role of instructive signals from the mesenchyme on endocrine cell differentiation earlier in the development. These results identified a complex pattern of cell commitment, dependent of the differentiation type of the epithelial cell, on the regional origin of the endoderm and the associated mesenchyme.
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PMID:Endoderm- and mesenchyme-dependent commitment of the differentiated epithelial cell types in the developing intestine of rat. 1264 70

Following massive small bowel resection (SBR) in mice, there are sustained increases in crypt depth and villus height, resulting in enhanced mucosal surface area. The early mechanisms responsible for resetting and sustaining this increase are presently not understood. We hypothesized that expansion of secretory lineages is an early and sustained component of the adaptive response. This was assessed in the ileum by quantitative morphometry at 12 h, 36 h, 7 days, and 28 days and by quantitative RT-PCR of marker mRNAs for proliferation and differentiated goblet, Paneth cell, and enterocyte genes at 12 h after 50% SBR or sham operation. As predicted, SBR elicited increases of both crypt and villus epithelial cells, which were sustained though the 28 days of the experiment. Significant increases in the overall number and percentage of both Paneth and goblet cells within intestinal epithelium occurred by 12 h and were sustained up to 28 days after SBR. The increases of goblet cells after SBR were initially observed within villi at 12 h, with marked increases occurring in crypts at 36 h and 7 days. Consistent with this finding, qRT-PCR demonstrated significant increases in the expression of mRNAs associated with proliferation (c-myc) and differentiated goblet cells (Tff3, Muc2) and Paneth cells (lysozyme), whereas mRNA associated with differentiated enterocytes (sucrase-isomaltase) remained unchanged. From these data, we speculate that early expansion of intestinal secretory lineages within the epithelium of the ileum occurs following SBR, possibly serving to amplify the signal responsible for initiating and sustaining intestinal adaptation.
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PMID:Rapid expansion of intestinal secretory lineages following a massive small bowel resection in mice. 1692 Jun 99

Fluorescence-activated cell sorting (FACS) is an essential tool for studies requiring isolation of distinct intestinal epithelial cell populations. Inconsistent or lack of reporting of the critical parameters associated with FACS methodologies has complicated interpretation, comparison, and reproduction of important findings. To address this problem a comprehensive multicenter study was designed to develop guidelines that limit experimental and data reporting variability and provide a foundation for accurate comparison of data between studies. Common methodologies and data reporting protocols for tissue dissociation, cell yield, cell viability, FACS, and postsort purity were established. Seven centers tested the standardized methods by FACS-isolating a specific crypt-based epithelial population (EpCAM+/CD44+) from murine small intestine. Genetic biomarkers for stem/progenitor (Lgr5 and Atoh 1) and differentiated cell lineages (lysozyme, mucin2, chromogranin A, and sucrase isomaltase) were interrogated in target and control populations to assess intra- and intercenter variability. Wilcoxon's rank sum test on gene expression levels showed limited intracenter variability between biological replicates. Principal component analysis demonstrated significant intercenter reproducibility among four centers. Analysis of data collected by standardized cell isolation methods and data reporting requirements readily identified methodological problems, indicating that standard reporting parameters facilitate post hoc error identification. These results indicate that the complexity of FACS isolation of target intestinal epithelial populations can be highly reproducible between biological replicates and different institutions by adherence to common cell isolation methods and FACS gating strategies. This study can be considered a foundation for continued method development and a starting point for investigators that are developing cell isolation expertise to study physiology and pathophysiology of the intestinal epithelium.
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PMID:A multicenter study to standardize reporting and analyses of fluorescence-activated cell-sorted murine intestinal epithelial cells. 2392 85

Intestinal epithelial stem cells (IESCs) can differentiate into all types of intestinal epithelial cells (IECs) and Leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) is a marker for IESC. Previous studies reported enhanced proliferation of IECs in diabetic mice. In this study, the in vitro differentiation of Lgr5 positive IESCs sorted from diabetic mice was further investigated. The diabetic mouse model was induced by streptozotocin (STZ), and crypt IECs were isolated from small intestines. Subsequently, Lgr5 positive IESCs were detected by flow cytometry (FCM) and sorted by magnetic activated cell sorting (MACS). Differentiation of the sorted IESCs was investigated by detecting the IEC markers in the diabetic mice using immunostaining, quantitative real-time reverse-transcription polymerase chain reaction (qRT-PCR), and Western blot analysis, which was compared with normal mice. We found that the proportion of Lgr5 positive cells in the crypt IECs of diabetic mice was higher than that of control mice (P < 0.05). Lgr5 positive IESCs could be significantly enriched in Lgr5 positive cell fraction sorted by MACS. Furthermore, the absorptive cell marker sucrase-isomaltase (SI) and the Paneth cell marker lysozyme 1 (Lyz1) were more highly expressed in the differentiated cells derived from Lgr5 positive IESCs of diabetic mice in vitro (P < 0.05). We demonstrate that the number of Lgr5 positive IESCs is significantly increased in the small intestines of STZ-induced diabetic mice. Lgr5 positive IESCs sorted from the diabetic mice can differentiate into a higher proportion of absorptive cells and Paneth cells in vitro. We characterized the expression of Lgr5 in the small intestine of diabetic mice, and sorted Lgr5 positive intestinal epithelial stem cells (IESCs) for investigating their differentiation in vitro. We proved that the quantity of Lgr5 positive IESCs was significantly increased in the small intestines of diabetic mice. IESCs sorted from the diabetic mice can differentiate into a higher proportion of absorptive cells and Paneth cells in vitro.
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PMID:Lgr5 positive stem cells sorted from small intestines of diabetic mice differentiate into higher proportion of absorptive cells and Paneth cells in vitro. 2612 64


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