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  • 1995-1999  (4)
  • diabetic retinopathy  (3)
  • Colorectal carcinoma, early stage  (1)
  • 66.30
Material
Years
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Diseases of the colon & rectum 40 (1997), S. 161-167 
    ISSN: 1530-0358
    Keywords: Heterogeneity ; Ki- ras [bdpoint mutation ; Colorectal carcinoma, early stage ; Tumorigenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract PURPOSE: The aim of this study was to elucidate pathways of carcinogenesis in the colon and rectum by investigating Ki-ras point mutation in different types of colorectal carcinomas in the early stage. METHODS: We analyzed rates of Ki-ras codon 12 mutations in 34 small, polypoid-type carcinomas (Tis or T1), 21 superficial-type carcinomas (Tis or T1), and 42 advanced carcinomas (T2, T3, and T4). RESULTS: Frequency of Ki-ras mutations in superficial-type carcinomas was 14.3 percent (3/21), which was significantly lower than 50 percent (17/34) in small polypoid carcinomas and 40.5 percent (17/42) in advanced carcinomas. These data suggest that another pathway of colorectal carcinogenesis that does not involve Ki-ras point mutation might exist. Among the 17 small polypoid carcinomas with Ki-ras point mutation in which both adenomatous and carcinomatous tissue were examined, 12 showed a mutation of the same type in both carcinomatous and adenomatous tissues. In two cases, mutation was present only in carcinomatous tissue and not in adenomatous tissue; in the other three cases, Ki-ras point mutation was present only in adenomatous tissue but not in carcinomatous tissue. CONCLUSIONS: These data suggest that carcinoma in a small polypoid lesion does not always develop from pre-existing adenoma with Ki-ras point mutation; in a small number of the polypoid-type early carcinomas, polyclonal composition concerning the Ki-ras gene may exist.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0428
    Keywords: Transgenic mice ; aldose reductase ; diabetic angiopathies ; diabetic retinopathy ; diabetic nephropathies
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the role of human aldose reductase (hAR) in the pathogenesis of diabetic complications, we generated transgenic mice carrying hAR cDNA driven by the murine MHC class I molecule promoter (hAR-Tg). Northern and Western blot analyses and immunoassay of hAR revealed that both hAR mRNA and the protein were expressed in all tissues tested. Thrombosis in renal vessels and fibrinous deposits in Bowman's capsule were observed in 6-week-old hAR-Tg mice fed a normal diet. Ingestion of a 30% glucose diet for 5 days caused sorbitol concentrations in the liver, kidney, and muscle of hAR-Tg mice to be elevated significantly. Seven-week-old hAR-Tg mice fed a 20% galactose diet for 7 days developed cataracts and occlusion of the retinochoroidal vessels, in addition to pathological changes in the kidney. Despite an elevated aldose reductase level in hAR-Tg mice and their intake of an aldose diet, no histopathological changes were found in other tissues, including the brain, lungs, heart, thymus, spleen, intestine, liver, muscle, spinal cord, or sciatic nerve. Results suggest that target organs of diabetic complications, such as the kidney, lens, and retina are sensitive to damage associated with a high level of AR expression, but other organs are not; the susceptibility of each organ to diabetic complications is determined by not only hAR but also other factors.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0428
    Keywords: Key words Transgenic mice ; aldose reductase ; diabetic angiopathies ; diabetic retinopathy ; diabetic nephropathies.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To investigate the role of human aldose reductase (hAR) in the pathogenesis of diabetic complications, we generated transgenic mice carrying hAR cDNA driven by the murine MHC class I molecule promoter (hAR-Tg). Northern and Western blot analyses and immunoassay of hAR revealed that both hAR mRNA and the protein were expressed in all tissues tested. Thrombosis in renal vessels and fibrinous deposits in Bowman's capsule were observed in 6-week-old hAR-Tg mice fed a normal diet. Ingestion of a 30 % glucose diet for 5 days caused sorbitol concentrations in the liver, kidney, and muscle of hAR-Tg mice to be elevated significantly. Seven-week-old hAR-Tg mice fed a 20 % galactose diet for 7 days developed cataracts and occlusion of the retinochoroidal vessels, in addition to pathological changes in the kidney. Despite an elevated aldose reductase level in hAR-Tg mice and their intake of an aldose diet, no histopathological changes were found in other tissues, including the brain, lungs, heart, thymus, spleen, intestine, liver, muscle, spinal cord, or sciatic nerve. Results suggest that target organs of diabetic complications, such as the kidney, lens, and retina are sensitive to damage associated with a high level of AR expression, but other organs are not; the susceptibility of each organ to diabetic complications is determined by not only hAR but also other factors. [Diabetologia (1995) 38: 255–261]
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0428
    Keywords: Keywords Vascular endothelial growth factor ; vascular permeability factor ; Goto-Kakisaki rat ; diabetic retinopathy ; ELISA ; immunohistochemistry.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary Vascular endothelial growth factor (VEGF) is a potent angiogenic factor. VEGF levels in ocular tissue of 6-, 12-, 18- and 28-week-old Goto-Kakizaki (GK) rats, a well-known model of non-insulin-dependent diabetes, were evaluated by highly sensitive ELISA. VEGF concentrations in the GK rat as well as in non-diabetic Wistar rat significantly decreased from the age of 6 weeks to 18 weeks. However, although VEGF concentrations in the Wistar rat continued to fall significantly from 18 to 28 weeks of age, the levels were maintained between 18 and 28 weeks of age in GK rats. Levels were significantly different between the GK and Wistar rats at 28 weeks of age. Results of immunohistochemical studies of the eyes of Wistar and GK rats at 28 weeks of age suggest diffuse distribution of this cytokine in cells of neural origin. Weak to moderate VEGF immunoreactivity was exhibited mainly in the ganglion cell layer, inner plexiform layer and inner/outer nuclear layers in rats with and without diabetes. However, in the retinal optic nerve fiber layer, retinal pigment epithelium and choroid, strong VEGF immunoreactivity was noted only in the GK rat. In conclusion, increased VEGF production in certain ocular tissue, similar to that in humans, is observed quite early, at least before the appearance of observable retinal changes in the diabetic GK rat. This also suggests that the GK rat can be used as a model of initial or latent phase diabetic retinopathy. [Diabetologia (1997) 40: 726–730]
    Type of Medium: Electronic Resource
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