BACKGROUND Abnormal Ca(2+) transients are often observed in heart muscles under a variety of pathophysiological conditions including ventricular tachycardia. To clarify whether these abnormal Ca(2+) transients can be attributed to abnormal action potential generation or abnormal Ca(2+) handling/excitation-contraction (EC) coupling, we developed a procedure to determine Ca(2+) and action potenti...

To investigate how intercellular coupling can be changed during Ca2+ overloading of ventricular muscle, we studied Ca2+ signals in individual cells and the histochemistry of the major gap junction channel, connexin43 (Cx43), using multicellular preparations. Papillary muscles were obtained from guinea pig ventricles and loaded with rhod-2. Sequential Ca2+ images of surface cells were obtained w...

The rate at which rat pancreatic lipase (glycerol-ester hydrolase, EC 3.1.1.3) hydrolyzes the esters of primary n-alcohols containing from 1 to 18 carbon atoms with fatty acids containing from 2 to 18 carbon atoms was determined. The speed of hydrolysis was influenced, apparently independently, by both the acyl and the alkyl chains. With respect to the fatty acid moiety, the esters of dodecanoi...

We evaluated the dose relationship between the antiproliferative and toxic effects of 5-fluorouracil (5-FU) on the ocular surface epithelium following experimental corneal epithelial wounding in rabbits. Central corneal epithelial defects 8 mm in diameter were made using n-heptanol. 5-FU (0.05 mg, 0.5 mg, or 5.0 mg per day in divided doses) or saline was applied topically for up to 18 days begi...

After debridement of the entire corneal epithelium with n-heptanol, two groups of rabbit corneas were segregated according to the extent of corneal neovascularization. Using a new topographic goblet-cell counting method and routine histology, the authors have reexamined the process of conjunctival transdifferentiation and compared the changes of goblet-cell density and morphology between nonvas...

Two-component interactions between (perfluorooctyl) heptanol (F8H7OH) and dipalmitoylphosphatidylcholine (DPPC), which is a major component of pulmonary surfactants in mammals, were systematically elucidated using Langmuir monolayers and Langmuir-Blodgett (LB) films of the compounds. The interactions such as the miscibility of the compounds and their phase behavior were examined from thermodyna...

Whole cell patch-clamp techniques were used to investigate amiloride-sensitive sodium conductance (G(Na)) in the everted initial collecting tubule of Ambystoma. Accessibility to both the apical and basolateral membranes made this preparation ideal for studying the regulation of sodium transport by insulin. G(Na) accounted for 20% of total cell conductance (G(T)) under control conditions. A rest...