Home About us Contact
|
Home About us Contact | ||
|
|
||
Min Mice (min + mouse)
Selected AbstractsFunctional colonography of Min mice using dark lumen dynamic contrast-enhanced MRIMAGNETIC RESONANCE IN MEDICINE, Issue 3 2008C. Chad Quarles Abstract Dark lumen MRI colonography detects colonic polyps by minimization of the intestinal lumen signal intensity. Here we validate the use of perfluorinated oil as an intestinal-filling agent for dark lumen MRI studies in mice, enabling the physiological characterization of colonic polyps by dynamic contrast-enhanced MRI. In control and Min (multiple intestinal neoplasia) mice with and without pretreatment with oral dextran sodium sulfate (DSS), polyps as small as 0.94 mm diameter were consistently identified using standard 2D gradient echo imaging (voxel size, 0.23 × 0.16 × 0.5 mm). In serial studies, polyp growth rates were heterogeneous with an average ,5% increase in polyp volume per day. In DSS-treated control mice the colon wall contrast agent extravasation rate constant, Ktrans, and extravascular extracellular space volume fraction, ve, values were measured for the first time and found to be 0.10 ± 0.03 min,1 and 0.23 ± 0.09, respectively. In DSS-treated Min mice, polyp Ktrans values (0.09 ± 0.04 min,1) were similar to those in the colon wall but the ve values were substantially lower (0.16 ± 0.03), suggesting increased cellular density. The functional dark-lumen colonography approach described herein provides new opportunities for the noninvasive assessment of gastrointestinal disease pathology and treatment response in mouse models. Magn Reson Med 60:718,726, 2008. © 2008 Wiley-Liss, Inc. [source] The role of NO synthases in arginine-dependent small intestinal and colonic carcinogenesisMOLECULAR CARCINOGENESIS, Issue 2 2006Hagit F. Yerushalmi Abstract Arginine is catabolized by NOS2 and other nitric oxide synthases to form nitric oxide. We evaluated the roles of dietary arginine and Nos2 in Apc -dependent intestinal tumorigenesis in Min mice with and without a functional Nos2 gene. NOS2 protein was expressed only in intestinal tissues of ApcMin/+Nos2+/+ mice. NOS3 expression was higher in intestinal tissues of mice lacking Nos2, mainly in the small intestine. When diet was supplemented with arginine (0.2% and 2% in drinking water), lack of Nos2 results in decreased tumorigenesis in both small intestine and colon. In Nos2 knockout mice, supplemental arginine (up to 2%) caused a decrease in small intestinal tumor number and size. The arginine-dependent decrease was associated with an increase in nitrotyrosine formation and apoptosis in the region of intestinal stem cells. Mice expressing Nos2 did not show these changes. These mice did, however, show an arginine-dependent increase in colon tumor number and incidence, while no effect on apoptosis was seen. These changes were associated with increased nitrotyrosine formation in epithelial cells. Mice lacking Nos2 did not show changes in tumorigenesis or nitrotyrosine formation, while demonstrating an arginine-dependent increase in apoptosis. These data suggest that Nos2 and dietary arginine have significant effects on intestinal and colonic tumorigenesis in Min mice. In both tissues, loss of Nos2 is associated with decreased tumorigenesis when mice are supplemented with dietary arginine. In the small intestine, Nos2 prevents the arginine-induced decrease in tumor number and size, which is associated with NOS3 expression and increased apoptosis. In the colon, Nos2 is required for the arginine-induced increase in tumor number and incidence. © 2005 Wiley-Liss, Inc. [source] Relationships between intestinal polyp formation and fatty acid levels in plasma, erythrocytes, and intestinal polyps in Min miceCANCER SCIENCE, Issue 12 2008Kiyonori Kuriki We have reported that a hyperlipidemic state is characteristic of Apc -deficient Min mice with multiple intestinal polyps. In our earlier case-control study, colorectal cancer risk showed positive relationships with erythrocyte membrane compositions of palmitic and oleic acids, but negative links with linoleic and arachidonic acids. To examine the roles of fatty acids in intestinal polyp formation, levels in plasma, erythrocytes, and intestinal polyps in Min mice were compared with those in wild-type mice. A diet free of eicosapentaenoic and docosahexaenoic acids with antineoplastic effects was fed to all mice from 6 to 15 weeks of age. Fatty acid levels were measured using accelerated solvent extraction and gas,liquid chromatography. Min mice with a hyperlipidemic state and multiple intestinal polyps had elevated values for palmitic and oleic acids in plasma and erythrocytes (at least P < 0.05), and higher plasma level of linoleic acid (P < 0.05). Arachidonic acid was 24.5% lower in erythrocytes (P < 0.0005), but did not differ in plasma. In Min mice, moreover, oleic and arachidonic acids were 1.78 and 1.43 times higher, respectively, in intestinal polyps than in paired normal mucosa (P < 0.05 and P < 0.01, respectively), but linoleic acid was 31.9% lower (P < 0.001). The present study suggests that palmitic, oleic, and arachidonic acids play key roles in intestinal polyp formation, and demonstrates reduced erythrocyte arachidonic acid values of Min mice, in line with our previous findings for patients with sporadic colorectal cancers. (Cancer Sci 2008; 99: 2410,2416) [source] Food Restriction Inhibits the Growth of Intestinal Polyps in Multiple Intestinal Neoplasia MouseCANCER SCIENCE, Issue 3 2002Masakazu Kakuni The effect of food restriction (FR) on spontaneous intestinal carcinogenesis in multiple intestinal neoplasia (Min) mice was examined. Thirty male Min mice were allotted to ad libitum feeding control and 20% FR groups from six weeks of age until the end of the 13-week experimental period. Although the total number of visible intestinal polyps in the FR group was not significantly different from the control group value, a significant decrease in large-sized polyps (>2 mm) and an increase in small-sized polyps (>2 mm) were observed in the distal small intestine. In this segment, the percentage of apoptotic cells counted in intestinal polyps in the FR group was significantly higher than in the control group, the percentage of proliferating cell nuclear antigen (PCNA)-positive cells not being significantly different. These results indicate that the FR may inhibit the growth of intestinal polyps in the Min mouse, and that apoptosis contributed in part to the inhibitory effect. [source] | ||||||||||