To investigate whether extracellular matrix glycosaminoglycan hyaluronan (HA) modulates eosinophil activation and transforming growth factor (TGF)-beta production by eosinophils, human peripheral blood eosinophils (purity > 99%) from 12 patients with mild to moderate asthma or six healthy subjects were isolated and incubated with increasing concentrations of low molecular weight (mol wt) HA ( approximately 0.2 x 10(6) D) or high mol wt HA (3.0 to approximately 5.8 x 10(6) D). We found that the low mol wt HA has a pronounced effect on eosinophil survival in both patients with asthma and healthy subjects in a dose-dependent fashion on Days 2 and 4. Whereas the high mol wt HA had a smaller effect on eosinophil survival than did the low mol wt HA. The HA-mediated eosinophil survival was partially but significantly inhibited ( approximately 50% inhibition) by a blocking monoclonal antibody for CD44, a specific receptor of HA, and largely inhibited by an anti-granulocyte macrophage colony-stimulating factor (GM-CSF) neutralizing antibody but not by an anti-interleukin (IL)-3 or anti-IL-5 neutralizing antibody. In addition, the low mol wt HA increased GM-CSF messenger RNA (mRNA) expression and protein secretion by eosinophils in a dose-dependent fashion, suggesting that the HA-mediated eosinophil survival is due mainly to induction of GM-CSF release through partial CD44 signaling. Furthermore, we demonstrated that the low mol wt HA results in morphologic changes in eosinophils such as transforming from a round to a spindle shape and in homotypic aggregation, upregulates intercellular adhesion molecule-1 expression, and increases TGF-beta mRNA expression and protein secretion by eosinophils. These observations suggest previously unforeseen interactions between eosinophils and low mol wt extracellular matrix and, thus, novel pathways by which eosinophils may contribute to the regulation of airway inflammation and airway remodeling.

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Serum biochemical analysis was undertaken to study the pathophysiological details of emaciation disease of the tiger puffer fish Takifugu rubripes (Temminck and Schlegel). Serum parameters were measured by biochemical analysis using automated dry chemistry and gas chromatography/mass spectrometry (GC/MS). Serum concentrations of albumin, amylase, calcium, creatinine, glucose and total protein were significantly lower in the emaciated fish when compared with those of normal fish. Regression analyses found close correlation between concentrations of total protein, albumin, amylase, glucose and progress of the disease. In contrast, serum alanine aminotransferase increased significantly in emaciated fish indicating liver function disorder. Further, GC/MS metabolic profiling of the puffer serum showed that the profile of the emaciated fish was distinct to that of non-infected control. The serum content of amino acids including glycine, 5-oxo-proline and proline, and ascorbic acid, fumaric acid and glycerol increased significantly in serum in moderately emaciated fish. The serum glucose, linolenic acid and tyrosine level decreased significantly in the late phase of the disease. Our results clearly show that prolonged intestinal damage caused by myxosporean infection impairs absorption of nutrients, resulting in extreme emaciation.

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ABSTRACT. To test whether glycosphingolipids (GSLs) on the intestinal mucosa of rainbow trout (Oncorhynchus mykiss) serve as a binding receptor for Vibrio anguillarum, we analyzed neutral GSLs from rainbow trout intestinal mucosa and investigated the binding of bacteria to neutral GSLs. Two kinds of neutral GSLs, designated N-1 and N-2, were identified on high-performance thin-layer chromatography (TLC) plates. In TLC immunostaining tests, V. anguillarum bound only to galactosylceramide (GalCer), lactosylceramide and N-1 having the same TLC mobility as GalCer, but neither to glucosylceramide nor to N-2. These results suggest that N-1 is GalCer (Galβ1-1Cer) and also that N-1 (GalCer) on rainbow trout intestinal mucosa act as a receptor for V. anguillarum.