Biomedical subjects

Kathleen Liu

Publications and source records attributed to Kathleen Liu.

2 recordsLinked to original sources

PubMed2005

Formation of multicellular epithelial structures.

The kidney is primarily comprised of highly polarized epithelial cells. Much has been learned recently about the mechanisms of epithelial polarization. However, in most experimental systems the orientation of this polarity is determined by external cues, such as growth of epithelial cells on a filter support. When Madin-Darby canine kidney (MDCK) cells are grown instead in a three-dimensional (3D) collagen gel, the cells form hollow cysts lined by a monolayer of epithelial cells, with their apical surfaces all facing the central lumen. We have found that expression of a dominant-negative (DN) form of the small GTPase Rac1 causes an inversion of epithelial polarity, such that the apical surface of the cells instead faces the periphery of the cyst. This indicates that the establishment of polarity and the orientation of polarity can be experimentally separated by growing cells in a 3D collagen gel, where there is no filter support to provide an external cue for orientation. DN Rac1 causes a defect in the assembly of laminin into its normal basement membrane network, and addition of a high concentration of exogenous laminin rescues the inversion of polarity caused by DN Rac1.

Animals↗

PubMed2003

Management of acidosis during lung-protective ventilation in acute respiratory distress syndrome.

In ARDS, when acidosis complicates LPV, the goal of alkali therapy is to maintain arterial pH at a safe level (> or = 7.20). A pure respiratory acidosis generally does not require alkali therapy. If the Pplat is greater than 30 cm H2O, and the respiratory rate equals the upper limit (35-40 breaths/minute), then V(E) is slowly titrated down by approximately 1 L/hour, so that PaCO2 increases by 10 mm Hg/hour or less. Alkali therapy is indicated for either a metabolic acidosis or a mixed acidosis. The choice of buffer is based on the type of acidosis, cardiorespiratory status, and lung mechanics. Slow infusions of NaHCO3 can be used to treat non-anion gap metabolic acidosis and some forms of increased anion gap acidosis. Using NaHCO3 to treat type A (hypoxia-related) lactic acidosis can be hazardous, particularly under conditions of hypoxemia, inadequate circulation, and limited alveolar ventilation. Under these circumstances, THAM is the preferable buffer because it does not increase PaCO2 and is excreted by the kidneys. When renal failure is present, CRRT is indicated to manage acidosis. When ARDS is complicated by traumatic or hemorrhagic shock, overresuscitation with Cl(-)-rich solutions should be avoided to prevent metabolic acidosis.

Acidosis↗