Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0029713 (immaturity)
 4,335 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The early and late effects of a single high-dose irradiation (100 rad) in the pig small intestine have been studied by histoenzymology and electron microscopy and related to some functional data. 1) The initial atrophy induced by the irradiation appears late (on the 6th day), compared to other species. This is due to the fairly long regeneration time of the villi epithelium in the pig. 2) The initial lesions are similar to those observed in different experimental models (nuclear alterations, karyolytic bodies, etc.). They particularly involve the crypts, and are specially focused in the undifferentiated cells of GS phase or mitosis, but also in goblet and Paneth's cells. 3) The villi regeneration, over on the 23rd day, is preceeded by an active mitotic phase which first renews the undifferentiated cells. This mitotic activity, reaching its highest value on the 16th day, goes on during the whole regeneration period itself. 4) At the beginning, this regeneration is denoted by the high esterase activity of the crypt collar. It appears in many goblet cells and also in some absorptive cells which show, at once, some of the enzymatic activities of the striated border. However, for a short period, lipid absorption is quantitatively reduced. This is connected with the temporary cell immaturity (up to the 20th day) and to the poorly developed rough endoplasmic reticulum and Golgi apparatus. 5) Further on, the persistence of a malabsorption syndrome (lipids, calcium) is not connected, for the main point, with modifications of the morphology or the cytology of the villi (in spite of the abnormally high number of goblet cells and the presence of few pathologic absorptive cells). It is, in fact, related to the persistence of an inflammatory state of the lamina propria associated with an exudative enteropathy. The meaning of this last finding is not clear: it could depend on a primary infectious state due to the modifications of the endoluminal intestinal flora, or, rather, on a secondary infection supported by the trophic epithelial disturbances induced by a continuous vascular dyshoria due to the irradiation.
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PMID:High-dose irradiation in the pig small intestine. Histoenzymology and electron microscopic study. 40 73

Sequential chemotherapeutic regimens, primarily used in the treatment of hematopoietic malignancies, and employing ara-C as a basic antineoplastic agent induce mucosal alterations in the entire gastrointestinal tract. These are characterized by surface and glandular epithelial atypia, immaturity, and necrosis. Glandular regeneration is characteristically delayed leading to a state of intestinal aproliferative cytopenia. Other toxic intestinal changes include telangiectasia of blood vessels and the formation of intramural hematomas. Intestinal infections develop frequently and are complicated by peritonitis, liver abscesses, pneumatosis cystoides in testinalis and sepsis. These intestinal lesions are accompanied by a predictable clinical syndrome which begins concomitantly with ara-C infusions and is characterized by diarrhea, ileus, abdominal pain, hematemesis and melena, severe hypokalemia, hypocalcemia and a protein-losing enteropathy. Additional toxic manifestations induced by ara-C include transient weight gains, fever elevations and severe bone marrow depression. The genesis of the intestinal lesions is linked to the three day dose schedule of ara-C infusions which insures both arrest of the cycling intestinal cells in the S-phase and a high cytotoxic index. The severity of these lesions is markedly augmented by prior treatment with ara-C and cyclophosphamide which causes synchronization and probable recruitment of intestinal stem cells, respectively.
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PMID:Cytosine arabinoside induced gastrointestinal toxic alterations in sequential chemotherapeutic protocols: a clinical-pathologic study of 33 patients. 70 32