Effects of an aldose reductase inhibitor, SNK-860, on the histopathological changes of retinal tissues in a streptozotocin-induced diabetic rat model.

In order to clarify the mechanism of retinal tissue damage in diabetes mellitus, the effects of the inhibition of aldose reductase on the pathologic changes in the retina of streptozotocin-induced diabetic (STZ-diabetic) rats were examined histologically and histochemically. The STZ-diabetic animals were maintained with and without peroral administration of an aldose reductase inhibitor, SNK-860, and their retinas were examined microscopically after 12 months. Several abnormal changes observed; folding and edema in the retina, loss of pericytes in the retinal capillary walls, and thickening of basement membranes in the retinal capillaries, were significantly inhibited by SNK-860. Some of these changes were similar to those that had been previously noted in diabetic and galactosemic rats. These data suggest that the enhanced polyol metabolism may be involved in the diabetic changes of the retina.</p

Is increased fat content of hindmilk due to the size or the number of milk fat globules?

<p>Abstract</p> <p>Background</p> <p>It is known that the fat content of breast milk is higher in hindmilk than in foremilk. However, it has not been determined if this increased fat content results from an increase in the number of milk fat globules (MFGs), an increase in the size of MFGs, or both. This study aims to determine which factor plays the most important role.</p> <p>Methods</p> <p>Thirteen breastfeeding mothers were enrolled in the study and we obtained 52 samples from 26 breasts before (foremilk) and after (hindmilk) a breastfeeding session. The fat content was evaluated by creamatocrit (CrCt) values. MFG size was measured with the laser light scattering method. We compared CrCt values and MFG size between foremilk and hindmilk.</p> <p>Results</p> <p>Although the CrCt values were higher in the hindmilk (8.6 ± 3.6%) than in the foremilk (3.7 ± 1.7%), the MFG size did not change (4.2 ± 1.0 μm and 4.6 ± 2.1 μm, foremilk and hindmilk, respectively). There was no relationship between the changes in CrCt versus MFG size from foremilk to hindmilk.</p> <p>Conclusion</p> <p>The results indicate that the increase in fat content results mainly from the increased number of MFGs, which may be released into the milk flow as the mammary lobe becomes progressively emptied.</p

Crystal structure of a Ca2+-dependent regulator of flagellar motility reveals the open-closed structural transition

Sperm chemotaxis toward a chemoattractant is very important for the success of fertilization. Calaxin, a member of the neuronal calcium sensor protein family, directly acts on outer-arm dynein and regulates specific flagellar movement during sperm chemotaxis of ascidian, Ciona intestinalis. Here, we present the crystal structures of calaxin both in the open and closed states upon Ca2+ and Mg2+ binding. The crystal structures revealed that three of the four EF-hands of a calaxin molecule bound Ca2+ ions and that EF2 and EF3 played a critical role in the conformational transition between the open and closed states. The rotation of α7 and α8 helices induces a significant conformational change of a part of the α10 helix into the loop. The structural differences between the Ca2+- and Mg2+-bound forms indicates that EF3 in the closed state has a lower affinity for Mg2+, suggesting that calaxin tends to adopt the open state in Mg2+-bound form. SAXS data supports that Ca2+-binding causes the structural transition toward the closed state. The changes in the structural transition of the C-terminal domain may be required to bind outer-arm dynein. These results provide a novel mechanism for recognizing a target protein using a calcium sensor protein