<Emphasis Type="Italic">In vitro</Emphasis> and <Emphasis Type="Italic">ex vivo</Emphasis> effect of hyaluronic acid on erythrocyte flow properties

Background  

Hyaluronic acid (HA) is present in many tissues; its presence in serum may be related to certain inflammatory conditions, tissue damage, sepsis, liver malfunction and some malignancies. In the present work, our goal was to investigate the significance of hyaluronic acid effect on erythrocyte flow properties. Therefore we performed in vitro experiments incubating red blood cells (RBCs) with several HA concentrations. Afterwards, in order to corroborate the pathophysiological significance of the results obtained, we replicated the in vitro experiment with ex vivo RBCs from diagnosed rheumatoid arthritis (RA) patients, a serum HA-increasing pathology.     

Ribosomal RNA sequence phylogeny is not congruent with ascospore morphology among species in Ceratocystis sensu stricto

The genus Ceratocystis sensu stricto includes important fungal pathogens of woody and herbaceous plants. This genus is distinguished from species in Ceratocystis sensu lato by the presence of Chalara anamorphs. Ascospore shape has been used extensively in delineating Ceratocystis taxa, which show a large variety of ascospore shapes. Sequence analysis of one region of he 18S ribosomal RNA subunit and two regions of the 28S ribosomal RNA subunit showed that there was a majority of multiple substitutions at nucleotide sites and that there was a low transition/transversion ratio, T = 0.72. Both of these results suggest that these are well established, old species. Ascospore morphology, for the most part, was not congruent with the molecular phylogeny, and the use of morphological characters may be misleading in the taxonomy of these species.      

Giemsa-based cytological assessment of area,shape and nucleus:cytoplasm ratio of goblet cells of rabbit bulbar conjunctiva

Goblet cells were visualized in impression cytology specimens from bulbar conjunctiva of the rabbit eye using Giemsa staining. Highly magnified images were used to generate outlines of the goblet cells and their characteristic eccentric nuclei. Using sets of 10 cells from 15 cytology specimens, I found that the longest dimension of the goblet cells averaged 16.7 ± 2.3 μm, the shortest dimension averaged 14.4 ± 1.8 μm and the nucleus averaged 6.3 ± 0.8 μm. The goblet cells were ellipsoid in shape and the longest:shortest cell dimension ratio averaged 1.169 ± 0.091. The goblet cell areas ranged from 108 to 338 μm² (average 193 ± 50 μm²). The area could be predicted reliably from the longest and shortest dimensions (r² = 0.903). The areas of goblet cell nuclei were 15–58 μm² (average 33 ± μm²) and the nucleus:cytoplasm area fraction was predictably greater in smaller goblet cells and less in the larger goblet cells (Spearman correlation = 0.817). The nuclei were estimated to occupy an average of 9.5% of the cell volume. The differences in size, shape and nucleus:cytoplasm ratio may reflect differences in goblet cell maturation.     

Metalloendopeptidase EC3.4.24.15 is constitutively released from the exofacial leaflet of lipid rafts in GT1-7 cells

Metalloendopeptidase EC3.4.24.15 (EP24.15) is a physiologically important neuropeptide-degrading enzyme involved in the metabolism of multiple neuropeptides. The mechanism of release of EP24.15 from neuronal cells is multimodal, being both constitutive and stimulatable. Previous studies have characterized stimulated EP24.15 secretion, yet little is understood concerning constitutive release of the peptidase. Utilizing the mouse hypothalamic neuronal GT1-7 cell line, we demonstrate that EP24.15 exists within lipid rafts in the plasma membrane, and that the enzyme is localized to the exofacial leaflet of lipid rafts. Further, we have found that biotinylated EP24.15 on the extracellular surface is released into the cell media in a fashion similar to constitutive release. In addition, classical and non-classical secretion pathway inhibitors were employed to understand the release of EP24.15 into surrounding cell media. The non-classical secretion inhibitor glyburide, a blocker of ATP-sensitive K+ channels, decreased the amount of constitutively released EP24.15 in cell media of GT1-7 cells. With these data, we conclude that EP24.15 association with lipid rafts on the extracellular surface precedes constitutive release of the peptidase into the extracellular milieu for its action on neuropeptides.