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In order to determine the sensitivity and specificity of the test and to optimize experimental conditions utilizing the SBT in a rat model of chemotherapy-induced small intestinal damage. Initially, a 13C-sucrose dose-response study was performed in rats to determine an optimal sucrose concentration for the SBT; then applied to assess chemotherapy-induced intestinal damage. A further study was conducted to establish a SBT time-course of methotrexate-induced small intestinal damage and repair. Animals were killed at 96 or 144 h. A sucrose concentration of 0.25 g/ml was optimal (20% CV) for reproducibility and detection of intestinal damage. Maximal damage occurred at 72 h, small intestinal repair was initiated by 96 h and continued at 144 h post-MTX, as determined by the SBT and confirmed by biochemical analyses. Levels of sensitivity and specificity for the SBT were 98 and 94%, respectively. The SBT is a reliable non-invasive marker of small intestinal health and damage with a high degree of sensitivity and specificity. [ABSTRACT FROM AUTHOR]

A unique model of formula feeding in the neonatal rat was utilized to investigate the effects of an enterally delivered artificial milk formula on clinically relevant immunological and biological characteristics in the gut, compared to naturally reared pups. Hooded Wistar rat pups were randomly allocated to two treatment groups: formula-fed (FF) or naturally suckled (NS). A flexible silastic intra-gastric cannula was surgically implanted into the FF pups, through which an artificial rat milk supplement was continuously delivered from day 4 to day 10 of life. Rat pups were sacrificed at 10 days of age. Body weight, small intestinal weight, mucosal CD8(+) cell numbers, and ileal lactase activity in FF animals were significantly decreased compared to their NS counterparts (P < 0.05). Numbers of eosinophils, mucosal mast cells, CD4(+) T-cells, ileal villus height and gastric emptying times were significantly increased in FF pups (P < 0.05). We have developed a new rat model of artificial feeding which possesses important immunological and biological similarities to the premature human infant. [ABSTRACT FROM AUTHOR]

Chemotherapy or radiotherapy often cause mucosal damage in the gut (gut mucositis) in cancer patients. As a step to investigate mechanisms underlying subsequent intestinal repair, we have examined the expression profiles of hepatocyte growth factor (HGF) and its receptor c-met, two molecules previously implicated in tissue repair, in comparison to the histopathological and proliferative changes in a rat model of methotrexate-induced small intestinal mucositis. Histological analysis of the intestinal specimens revealed crypt loss and villus atrophy with damage maximal on day 5 after methotrexate injection, and normalization of mucosal structure commencing on day 6. Crypt cell proliferation was decreased dramatically on day 3, normalized on day 4 and up-regulated on days 5 and 6. HGF and c-met protein/mRNA expression was up-regulated between days 4 and 7, with the mRNA co-localizing to the crypt and lower villus epithelium. Therefore, following methotrexate injection, a decrease in crypt cell proliferation preceded histological damage, and conversely, crypt cell hyperproliferation preceded mucosal regeneration. Up-regulation of HGF and c-met coincided with crypt hyperproliferation and mucosal recovery, suggesting a role for HGF in intestinal repair following acute injury. The crypt epithelial localization of HGF and c-met implies an autocrine or paracrine mechanism of HGF action. [ABSTRACT FROM AUTHOR]

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Gut Zn homeostatic responses to low, replete, and excess dietary Zn (10, 150, and 400 mg Zn/kg, respectively) were compared in mice with (MT+/+) and without (MT−/−) metallothionein (MT) expression. MT concentrations decreased progressively from stomach (12.9 nmol Cd bound/g) to colon (4.6 nmol Cd bound/g). Small intestinal MT was increased in mice fed the 400-mg Zn/kg diet (+130%, duodenum; +56%, jejunum; +29%, terminal ileum), but not in the stomach, cecum and colon. Zn concentrations were much higher in the distal gut at increasing Zn intakes in MT+/+ mice but to a lesser extent in MT−/− mice. On the 10-mg Zn/kg diet, MT−/− mice had 45% more Zn in the jejunum/ileum than MT+/+ mice. In fasted (20 h) mice, Zn concentrations in all gut regions were similar to those of MT+/+ mice fed the 10-mg Zn/kg diet, irrespective of prior Zn intake or genotype. Liver MT quadrupled in mice fasted after the 10-mg Zn/kg diet but only doubled after the 400-mg Zn/kg diet, a trend also present in gut MT. Glucagon administration stimulated gut as well as liver MT, implicating it as a major component of the MT response to fasting. MT−/− mice had five times more variation than MT+/+ mice in plasma Zn over all dietary groups. Together, these findings demonstrate that without MT, there is little modification of regional gut Zn concentrations in response to extremes of dietary Zn and poorer regulation of Zn homeostasis. [ABSTRACT FROM AUTHOR]

There were high hopes and many predictions in the 1970s that the coatings industry would rapidly move to water-borne coatings. This did not occur in this very traditional and conservative industry. However, environmental legislation is now ensuring that more and more coatings systems are moving towards water-borne or high solids. This should not be viewed as a threat by the resin suppliers, but as a great opportunity. Small to medium size resin suppliers who are willing to tailor water-borne resin systems such as PUDs and hybrids to individual customer demands, will have an assured future. There is a very big market for functional coatings and for the resin systems designed for them. [ABSTRACT FROM AUTHOR]

The optimal conditions for opening of stomata in detached epidermis of the Crassulacean Acid Metabolism (CAM) plant Kalanchoe daigremontiana were determined. Stomatal opening in CO−free air was unaffected by light so subsequently all epidermal strips were incubated in the dark and in CO−free air. Apertures were maximal after 3 h incubation and were significantly greater at 15° C than 25° C. Thus stomata in isolated epidermis of this species can respond directly to temperature. Stomatal opening was greatest when the incubating buffer contained 17.6 mol m K, but decreased linearly with increasing K concentrations between 17.6 and 300 mol m; the decrease in aperture was shown to be associated with increasing osmotic potentials of the solutions. Reasons for this behaviour, which differs from that of many C and C species, are discussed. Stomatal apertures declined linearly upon incubation of epidermis on buffer solutions containing between 10 and 10 mol m abscisic acid (ABA). Hence stomata on isolated epidermis of K. daigremontiana respond to lower concentrations of ABA than those of any species reported previously. [ABSTRACT FROM AUTHOR]

Ulcerative colitis (UC) is a chronic inflammatory bowel disease characterized by cytokine driven inflammation that disrupts the mucosa and impedes intestinal structure and functions. Flightless I (Flii) is an immuno-modulatory protein is a member of the gelsolin family of actin-remodelling proteins that regulates cellular and inflammatory processes critical in tissue repair. Here we investigated its involvement in UC and show that Flii is significantly elevated in colonic tissues of patients with inflammatory bowel disease. Using an acute murine model of colitis, we characterised the contribution of Flii to UC using mice with low (Flii+/−), normal (Flii+/+) and high Flii (FliiTg/Tg). High levels of Flii resulted in significantly elevated disease severity index scores, increased rectal bleeding and degree of colon shortening whereas, low Flii expression decreased disease severity, reduced tissue inflammation and improved clinical indicators of UC. Mice with high levels of Flii had significantly increased histological disease severity and elevated mucosal damage with significantly increased inflammatory cell infiltrate and significantly higher levels of TNF-α, IFN-γ, IL-5 and IL-13 pro-inflammatory cytokines. Additionally, Flii overexpression resulted in decreased β-catenin levels, inhibited Wnt/β-catenin signalling and impaired regeneration of colonic crypts. These studies suggest that high levels of Flii, as is observed in patients with UC, may adversely affect mucosal healing via mechanisms involving Th1 and Th2 mediated tissue inflammation and Wnt/β-catenin signalling pathway. [ABSTRACT FROM AUTHOR]