Neutral and DEAE dextrans as tracers for assessing lung microvascular barrier permeability and integrity

Abstract

Steady-state lymph-to-plasma concentration ratios (L/Ps) of neutral dextrans, cationic DEAE dextrans, and endogenous proteins were determined under normal and increased permeability conditions in six unanesthetized yearling sheep prepared with chronic lung lymph fistulas. Fluorescent dextrans with radii ranging from 1 to 30 nm were intravenously infused, and after 24 h, perilla ketone (PK) was given to alter permeability while the dextran infusion was maintained. Plasma and lymph samples were collected before and after PK administration and analyzed for dextran and protein concentrations after high-performance liquid chromatography size separation. Under both baseline and increased permeability conditions, DEAE dextrans had higher L/Ps than neutral dextrans of similar size but lower L/Ps than proteins of similar size. Comparison of L/Ps before and after PK revealed that the percentage change in permeability for neutral and DEAE dextrans was significantly larger than that for proteins. These results suggest that 1) the pulmonary microvascular barrier behaves as a net negative barrier, 2) some transport mechanisms for proteins and dextrans are different, and 3) neutral and cationic dextrans are more sensitive markers than proteins of the same size for assessing changes in pulmonary capillary permeability.

Factors Associated with Risky Sexual Practices among Female Sex Workers in Karnataka, India

“…Evidence from research in India suggests that consistent condom use is considerably high with commercial partners [29], [32], [33], but has remained low with non-commercial partners [34]. The low level of condom use in non-commercial relationships can be due to the intimacy and trust involved in such relationships [35]; condom use in such relationships is most often perceived as a symbol of infidelity and fosters mistrust [36]. Further, the considerable proportion of FSWs involved in concurrent relationships coupled with high inconsistent condom use can lead to the transmission of STI/HIV infection at a much faster rate.…”

Pleural fluid exchange in rabbits

“…With this method the fluorescence values (proportional to concentration) are associated with elution times, which are related to a specific MW dextran. The elution times were translated to a MW as previously described 5 …”

“…Size-exclusion HPLC was performed at room temperature using a TSKgel 4000PW size exclusion column chromatograph (60 cm × 7.5 mm ID, Toso Hass, Montgomeryville, PA) and a guard column (7.5 cm × 7.5 mm ID Toso Hass) using a 0.3-M sodium nitrate mobile phase as previously described for a similar mobile phase. 5 From the column, the sample was passed into a fluorescence spectrophotometer F4500 (Hitachi, Tokyo, Japan). Multi-Wavelength Time Scan Program (Hitachi) software was used to interface with the spectrophotometer and excite the labelled molecules at the appropriate wavelength (FITC at 490 nm).…”

Matrix proteoglycans as effector molecules for epithelial cell function

“…In the kidney, anionic sites in the glomerular basement membrane are composed primarily of heparan sulphate proteoglycans, which provide the main charge-selective barrier to plasma proteins [36,37]. The pulmonary microvascular barrier behaves as a net negative charge [38] and, although heparan sulphate is the most abundant of the negatively charged components in the alveolar basement membrane, it is visualisation of sulphation in the extracellular matrix was performed using high iron diamine (HID), which binds to sulphates in lung tissue. The HID reaction product forms discrete 5-12 nm silver particles following appropriate intensification and is seen as discrete dark spots [29].…”