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  • peptone  (2)
  • proliferation  (2)
  • α-difluoromethylornithine  (2)
  • 1
    ISSN: 1573-2568
    Keywords: enterogastrone ; peptone ; colon ; intragastric titration
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract The purpose of this study was to examine the effect of perfusion of the colon with a fatty acid (oleic acid) on peptone-stimulated gastric acid secretion and release of gastrin in conscious dogs. Gastric acid secretion was monitored by continuous intragastric titration. Perfusion of the colon with sodium oleate (24 mmol/hr) inhibited gastric acid secretion (14.2±2.6 meq/hr) stimulated by a peptone meal (1%) significantly (P〈0.05) when compared to perfusion of the colon with saline alone (20.1±1.6 meq/hr). The serum elevation, in gastrin in response to intragastric instillation of the peptone meal was not affected by the colonic perfusion of oleic acid. Plasma concentrations of peptide YY (PYY) increased significantly in response to perfusion of the colon with saline or sodium oleate, and the integrated release of PYY in response to sodium oleate 16.9±2.8 ng (60–120) min/ml] was significantly greater than the response to saline [3.1±0.7 ng (60–120) min/ml]. The results of this study indicate that inhibition of gastric acid secretion by perfusion of the colon with fat is not due to an inhibition of gastrin release. In addition, because PYY is an inhibitor of gastric acid secretion, it is possible that PYY participates as an inhibitor of gastric acid secretion by the colon.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-0646
    Keywords: polyamines ; cancer ; 2-deoxy-D-glucose ; α-difluoromethylornithine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Summary The glycolytic inhibitor, 2-deoxy-D-glucose (2-DG), has been shown to inhibit the growth of certain cancers. α-Difluoromethylornithine (DFMO) is an irreversible inhibitor of ornithine decarboxylase (ODC), the ratelimiting enzyme in polyamine biosynthesis. DFMO has been shown to inhibit cancer growth in a number of models. The present study was designed to investigate the effects of 2-DG alone and combined with DFMO on MC-26 mouse colon adenocarcinoma tumors growing in vivo. Twenty-eight male Balb/c mice were inoculated with 250,000 MC-26 cells, and then randomized into four groups of 7 each: group I served as control; group II received DFMO (3% in drinking water); group III received 2-DG (500 mg/kg/d IP); group IV received a combination of 2-DG and DFMO. Treatment began 5 days after tumor cell inoculation. MC-26 tumor area was reduced 73% by DFMO compared to a 24% reduction caused by 2-DG. The tumor weight was reduced 80% by DFMO and 52% by 2-DG. The tumor contents of DNA, RNA, and protein were significantly reduced by DFMO but not 2-DG. The tumor concentration of the polyamines putrescine and spermidine were reduced by DFMO alone or combined with 2-DG while spermine levels remained unchanged. 2-DG alone did not alter polyamine levels. These results indicate that both 2-DG and DFMO, when added as single agents, inhibit tumor growth. However, the addition of 2-DG to the DFMO regimen inhibited the antitumor effects of DFMO. Survival studies performed on MC-26 cells in vitro corroborated the antagonisms between DFMO and 2-DG that were shown in vivo.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-2568
    Keywords: burns ; starvation ; gut ; apoptosis ; proliferation ; rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Maintenance of gut mucosal homeostasis depends on a balance between cell proliferation and cell death. Gut mucosal integrity is impaired after severe burn and during starvation. We determined the effect of burn, starvation, and the combination of both on small bowel epithelial apoptosis and proliferation. Fifty adult male Fischer 344 rats (260–300 g) received a 60% full-thickness scald burn and were randomly divided into fed and starved groups. Small intestine was taken at 12, 24, and 48 hr after injury. All animals in the 12-hr group were starved while recovering from anesthesia. Apoptosis was quantified by immunohistochemical staining (TUNEL) and mucosal proliferation was determined by bromodeoxyuridine (BrdU) incorporation. The apoptotic index was higher in burned rats compared to controls at 12 hr after burn; both these groups were starved (P 〈 0.05). At 24 and 48 hr after burn, apoptosis was highest in the starved groups, with no additional effects of burn (P 〈 0.05). Mucosal epithelial cell proliferation was not different between groups at any time point. In conclusion, burn and starvation both increase apoptosis in the small bowel mucosa; however, these effects are not additive. Apoptosis could be attenuated by enteral feeding, which delineates the importance of early enteral feeding initiation after injury to maintain mucosal integrity.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1573-2568
    Keywords: bombesin ; carbachol ; peptone ; Fischer 344 rats
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We have examined the release of gastrin and somatostatin from the isolated perfused stomach of rats of three different age groups (4 months, 12 months, and 24 months old) in response to bombesin and carbachol. The basal release of gastrin was diminished in 24-month-old rats. Basal somatostatin release showed an age-related decrease. Bombesin (10−10 and 10−9 M) and carbachol (10−8 and 10−7 M) stimulated gastrin release in each age group. The integrated release of gastrin in response to bombesin (10−10 and 10−9 M) or carbachol (10−8 M) did not differ among the three age groups, although integrated gastrin release in response to carbachol (10−7 M) decreased in 24-month-old rats. Bombesin-stimulated release of somatostatin decreased in 12- and 24-month-old rats. Carbachol inhibited release of somatostatin in each age group. Compared with 4-month-old rats, the inhibition of somatostatin release by carbachol was less in 24-month-old rats at 10−8 and 10−7 M, and less in 12-month-old rats at 10−7 M. The decreased basal gastrin secretion and well-preserved gastrin response were further confirmed in conscious aged rats tested by means of oral gavage with 10% peptone. Our findings indicate that gastrin response to the stimuli is well preserved with aging, whereas the response of somatostatin diminishes in an age-related manner. Aging has different effects on the release of gastrin and somatostatin from the rat stomach.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Digestive diseases and sciences 38 (1993), S. 410-416 
    ISSN: 1573-2568
    Keywords: aging ; enterectomy ; disaccharidase ; proliferation ; differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Two groups of male Fisher 344 rats (young: 4 months old; aged: 25 months old) underwent either 70% distal small bowel resection or sham operation (small bowel transection). Rats from each treatment group of each age were sacrificed on the 10th (N=15: young rats;N=13: aged rats) or 20th (N=15: young;N=13: aged) postoperative day (POD), and the duodenal mucosa was weighed and assayed for DNA, RNA, and protein contents, as well as for specific activities of the disaccharidase, sucrase, maltase, and lactase. Compared to the sham operation, distal small bowel resection significantly increased DNA by 48%, RNA by 122%, and protein by 75% in young rats and DNA by 40%, RNA by 92%, and protein by 71% in aged rats on the 20th POD. Both young and aged rats showed similar adaptive hyperplasia on the 10th POD. On the 20th POD after distal small bowel resection, specific activities of all tested enzymes were significantly increased in young rats (sucrase +86%, maltase +110% and lactase +64%), but showed no significant changes in aged rats. These findings suggest that the duodenum of aged rats may have sufficient proliferative potential to respond to distal small bowel resection, but that the mechanisms governing return of function in response to distal small bowel resection are inhibited in aged rats, compared to those mechanisms in the young.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-0646
    Keywords: cancer ; cyclosporine ; pancreas ; colon ; polyamines ; α-difluoromethylornithine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract α-Difluoromethylornithine (DFMO) is a known irreversible inhibitor of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis. Cyclosporine (CsA) has been reported to inhibit ODC activity in vitro. In the present study, we compared the effects of DFMO and CsA on growth, survival, and polyamine levels in mouse colon cancer (MC-26) and hamster pancreatic cancer (H2T) cells in vitro. The growth and survival of MC-26 and H2T cells were inhibited by both DFMO and CsA. However, H2T cells were observed to be significantly more sensitive than MC-26 cells to both CsA and DFMO. The inhibitory effects of CsA were blocked by the addition of the polyamine, putrescine, in both MC-26 and H2T cells. Polyamine levels were altered significantly in both MC-26 and H2T cells treated with CsA and DFMO. However, the profile of these alterations differed between MC-26 and H2T cell lines. Putrescine and spermidine levels in MC-26 cells were more sensitive to DFMO inhibition than were H2T cells. Spermine levels were consistently elevated in MC-26 cells exposed to CsA or DFMO, while the level of spermine in H2T cells decreased significantly in response to the same drugs. These results suggest that CsA and DFMO exhibit different effects on colon and pancreatic cancer growth in vitro. In addition, the differences in the sensitivity of pancreatic and colon cancer to CsA and DFMO indicate potentially important differences in polyamine metabolism between the two cell lines.
    Type of Medium: Electronic Resource
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