No abstract

-Fructosamine and glycated hemoglobin (HbA 1c ) concentrations were measured simultaneously in 222 dogs (96 healthy and 126 sick dogs). The dogs were divided into 3 groups according to the glucose concentration: hypo, hyper and euglycaemic dogs. Serum fructosamine concentrations were measured by the reduction test with nitroblue tetrazolium. A turbidimetric inhibition immunoassay and specific polyclonal antibodies were used to evaluate glycated hemoglobin concentrations. A significant correlation was found between glucose concentration and either fructosamine (r = 0.63, p < 0.0001) or glycated hemoglobin (r = 0.82, p < 0.0001). The correlation was higher in hyperglycaemic dogs for fructosamine (r = 0.80, p < 0.0001) and in hypoglycaemic dogs for glycated hemoglobin (r = 0.91, p < 0.005). We found a significant correlation between serum fructosamine and glycated hemoglobin (r = 0.65, p < 0.0001) when all the dogs were studied. A significant correlation was observed between serum fructosamine and glycated hemoglobin only in hyperglycaemic dogs (r = 0.82, p < 0.0003). Thus, fructosamine and HbA1c may be considered for use in screening tests for diabetes mellitus in dogs and clinical tests for monitoring control and evaluation of the diabetic animal's response to treatment. The choice of the analytical assay depends on the characteristic and analytical opportunities of the laboratory, as well as the number of serum samples to be analysed.

No abstract

No abstract

Lipopolysaccharide (LPS) endotoxin is a causative agent of sepsis. The aim of this study was to examine LPS effects on intestinal fructose absorption and to decipher mechanisms. Sepsis was induced by intravenous injection of LPS in rabbits. The ultrastructural study and DNA fragmentation patterns were identical in the intestine of LPS and sham animals. LPS treatment reduced fructose absorption altering both mucosal-to-serosal transepithelial fluxes and uptake into brush border membrane vesicles (BBMVs). Cytochalasin B was ineffective on fructose uptake, indicating that GLUT5, but not GLUT2, transport activity was targeted. GLUT5 protein levels in BBMvs were lower in LPS than in sham-injected rabbits. Thus lower fructose transport resulted from lower levels of GLUT5 protein. LPS treatment decreased GLUT5 levels by proteasome-dependent degradation. Specific inhibitors of PKC, PKA, and MAP kinases (p38MAPK, JNK, MEK1/2) protected fructose uptake from adverse LPS effect. Moreover, a TNF-alpha antagonist blocked LPS action on fructose uptake. We conclude that intestinal fructose transport inhibition by LPS is associated with diminished GLUT5 numbers in the brush border membrane of enterocytes triggered by activation of several interrelated signaling cascades and proteasome degradation.

No abstract

Lipopolysaccharide (LPS) is an endotoxin causing sepsis. Studies from our laboratory revealed impaired intestinal absorption of L-leucine and D-fructose in LPS-treated rabbits. The aim of this study was to examine intestinal D-galactose transport following intravenous administration of LPS in the rabbit and to identify the cellular mechanisms driving this process. Endotoxin treatment diminished the buildup of D-galactose in intestinal tissue, the mucosal to serosal transepithelial flux of the sugar and its uptake by brush border membrane vesicles (BBMVs). Intracellular signaling pathways associated with protein kinase C (PKC), protein kinase A (PKA), p38 mitogen-activated protein kinase (p38MAPK), Jun N-terminal kinase (JNK), MAPK/extracellular signal-regulated kinases 1 and 2 (MEK1/2) and proteasome were found to be involved in this reduction in sugar uptake. Na(+)/glucose cotransporter 1 (SGLT1) protein levels in BBMVs were lower for LPS-treated animals than control animals. These findings indicate that LPS inhibits the intestinal absorption of D-galactose via a complex cellular mechanism that could involve posttranscriptional regulation of the SGLT1 transporter.

A method for assaying canine glycosylated haemoglobin was evaluated. The method is a turbidimetric inhibition immunoassay and the final reaction is bichromatically measured using a multichannel automatic analyser. Within-run coefficients of variation (2.07 to 4.46 per cent) were permissible, but between-run coefficients of variation (2.10 to 8.25 per cent) were slightly more elevated. The detection limit of this assay is 0.052 per cent. A sample dilution of 10 microliters of sample and 500 microliters of haemolysing reagent is recommended for routine analysis of canine blood samples. A normal reference interval of 1.39 +/- 0.70 per cent was obtained from the glycosylated haemoglobin analysis in 82 healthy dogs and no statistically significant differences in relation to age or gender were observed. Some changes in glycosylated haemoglobin concentrations were noted throughout the ovarian cycle, although differences between dogs were evident. Since this assay specifically measures the glycosylated haemoglobin content in canine blood samples, it could be very useful for monitoring diabetic dogs.