Five steps in leukocyte extravasation in the microcirculation by chemoattractants

For in vivo study of the phenomena observed in vitro, PMN (polymorphonuclear leukocyte) extravasation was analysed quantitatively in the microcirculation of the hamster cheek pouch using a video system. Topical application of leukotriene B4 or N-formyl-methionylleucyl- phenylalanine increased dose dependently the number of PMNs adhering to the venules. Eighty to 90% of the adhering PMNs disappeared from the vascular lumen into the venular wall within 10-12 rain after the adhesion. After PMNs had passed through the endothelial cell layer, they remained in the venular wall for more than 30 min after application of the chemoattractants and appeared in the extravascular space. Thus, the process could be divided into five steps: (1) rolling and (2) adhesion to the endothelium, (3) passage through the endothelial layer (4) remaining in the venular wall, and (5) passage through the basement membrane

Expression and Trafficking of the γ Subunit of Na,K-ATPase in Hypertonically Challenged IMCD3 Cells

The γ subunit (FXYD2) of Na,K-ATPase is an important regulator of the sodium pump. In this investigation we have analysed the trafficking of γ to the plasma membrane in cultures of inner medullary collecting duct cells (IMCD3) following acute hypertonic challenge and brefeldin A (BFA) treatment. Following hypertonic challenging for 24 hr immunofluorescence labeling revealed initial co-localization of the γ subunit and 58K Golgi protein in the cytoplasm, but no co-localization of α1 and Golgi protein. Exposure of the challenged cells to BFA prevented the subsequent incorporation of γ into the basolateral plasma membrane. The γ subunit instead remained in cytoplasmic vesicles while cell proliferation and cell viability decreased simultaneously. Following removal of BFA from the hypertonic medium the IMCD3 cells recovered with distinct expression of γ in the basolateral membrane. The α1 subunit was only marginally influenced by BFA. The results demonstrate that the γ subunit trafficks to the plasma membrane via the Golgi apparatus, despite the absence of a signal sequence. The results also suggest that the γ and α subunits do not traffic together to the plasma membrane, and that the γ and α subunit have different turnover rates during these experimental conditions

Associations of Renal Vascular Resistance With Albuminuria and Other Macroangiopathy in Type 2 Diabetic Patients

OBJECTIVE—Albuminuria can be caused by endothelial dysfunction as a result of ischemic nephropathy rather than classic diabetic nephropathy. We studied whether renal vascular resistance (resistive index [RI]) of the main renal arteries could be associated with albuminuria and further assessed the relationship between RI and aorta stiffness measured by brachial-ankle pulse-wave velocity (baPWV)