Separation of hepatocytes of different acinar zones by flow cytometry.

Hepatocytes in the proximal (zone 1) and distal (zone 3) regions of the liver acinus are selectively stained by perfusion of the isolated rat liver with 0.2-20 microM acridine orange (AO). After 10-60 min of anterograde perfusion, AO fluorescence is visible in zone 1 cells, whereas retrograde perfusion stains cells of zone 3.

Hepatobiliary transport of the anionic organomercury compound (mersalyl) is carrier mediated.

The hepatobiliary excretion of the anionic organic mercury compound (mersalyl) was studied in the isolated perfused rat liver and in isolated rat liver plasma membrane vesicles. In the isolated perfused liver, mersalyl is immediately taken up from the perfusion medium and concentratively excreted into bile. Uptake is characterized by saturation kinetics (S)0.

Genetic mapping in Xenopus laevis: eight linkage groups established.

Inheritance of alleles at 29 electrophoretically detected protein loci and one pigment locus (albinism) was analyzed in Xenopus laevis by backcrossing multiply heterozygous individuals generated by intersubspecies hybridization. Pairwise linkage tests revealed eight classical linkage groups. These groups have been provisionally numbered from 1 to 8 in an arbitrarily chosen order.

Volume-regulatory K+ fluxes in the isolated perfused rat liver: characterization by ion transport inhibitors.

Net hepatic release and uptake of K+ were examined in isolated perfused rat livers subjected to a 10-min period of hypotonic stress. Effluent Na+, K+, and Ca2+ activities were monitored throughout. Initiation and termination of hypotonic stress triggered sharp transient (less than 1 min) changes in effluent ion activities that indicated net water movement into and out of the liver, respectively.

Identification of a second active site in laminin for promotion of cell adhesion and migration and inhibition of in vivo melanoma lung colonization.

Previously we reported that a pentapeptide (Tyr-Ile-Gly-Ser-Arg or YIGSR) from domain III of the B1 chain of laminin is a cell attachment site with the ability to stimulate cell adhesion and migration and to block experimental metastases. Here we report studies on the activities of synthetic peptides that cover domain III and report a second biologically active peptide PDSGR from this domain with activities similar to YIGSR. We also show that cyclic YIGSR is more potent in these assays than the linear peptide as expected since this sequence on laminin is bracketed by cysteines.

Inward-rectifying potassium channels in rat hepatocytes.

The patch-clamp technique has been used to investigate single-channel and whole cell conductances in freshly isolated rat hepatocytes. Whole cell experiments, with high (144 mM) intracellular and extracellular potassium as the principal conductive species, show some variation between cells in the current-voltage relationship (mean whole-cell conductance at physiological potentials being 2.7 nS).

Interaction of different strains of Entamoeba histolytica with target cells: characterization of electrophysiological and morphological features.

Two strains of Entamoeba histolytica with pathogenic zymodemes (SFL3, HK9), one strain with non-pathogenic zymodeme ("Bru") and one non-pathogenic Entamoeba sp. strain ("cold strain"), were investigated with respect to their interaction with target cells. Three test systems were used: 1) direct microscopical observation and qualitative as well as quantitative evaluation of contact and binding events with MDCK cells as targets, 2) kinetics of cytotoxic activity as measured by means of chromium release from 51Cr-labelled K562 cells, and 3) electrophysiological observations with freshly prepared mouse liver cells.

Voltage-driven, taurocholate-dependent secretion in isolated hepatocyte couplets.

Bile formation by the liver is largely dependent on the transport of bile acids by hepatocytes. This process is thought to result from Na-coupled uptake of bile acids into the cell and voltage-dependent, carrier-mediated transport from cell to canaliculus. However, the dependence of bile secretion on membrane potential has not yet been observed.

Membrane potential measurements in isolated rat liver plasma membrane vesicles: effect of transmembrane ion concentration gradients.

In isolated basolateral and canalicular rat liver plasma membrane vesicles the membrane potential (measured with DiS-C2 (5] varied with transmembrane concentration gradients of Na+, K+ and Cl- revealing the following ion permeabilities: basolateral vesicles: PNa/PK: 0.76, PCl/PK: 0.45 and canalicular vesicles: PNa/PK: 0.

Effect of hypertonic stress on liver cell volume, bile flow, and volume-regulatory K+ fluxes.

Net hepatic uptake and release of K+ were studied in the isolated-perfused rat liver subjected to a 10-min period of hyperosmotic stress by addition of 80 mM mannitol or sucrose to the perfusing solution. Bile flow and effluent Na+, K+, and Ca2+ activities were monitored throughout. Upon initiation of hypertonic stress, a sharp transient dilution of effluent ion activities indicated hepatic water losses that were larger and occurred more rapidly with sucrose than with mannitol.

Sex linkage of malic enzyme in Xenopus laevis.

Genetic analysis of mME variants (mitochondrial malic enzyme, E.C. 1.

Differential regulation of growth and invasiveness of MCF-7 breast cancer cells by antiestrogens.

Estrogen increases the ability of the estrogen-dependent MCF-7 human breast cancer cell line to both proliferate and invade through an artificial basement membrane. In studying the response of MCF-7 cells to various antiestrogens, we found that 4-hydroxytamoxifen and tamoxifen inhibited cell proliferation but increased their invasiveness. In contrast, the structurally unrelated benzothiophene antiestrogens, LY117018 and LY156758, were potent antiproliferative agents which did not stimulate invasiveness.

Mechanisms of bile secretion: insights from the isolated rat hepatocyte couplet.

This article reviews recent studies that have characterized the isolated rat hepatocyte couplet as a primary unit of canalicular bile formation. This cell culture system is proving to be particularly useful for identifying primary canalicular choleretics and for elucidating mechanisms of canalicular bile formation by electrophysiologic, fluorescent, and quantitative microscopic techniques.

A simple paralleling instrument for superimposing radiographs of the molar regions.

A simple, disposable paralleling device to produce identical radiographs of the maxillary and mandibular molar regions is described. Its precision was determined by taking serial radiographs of several patients. No deformations were found when enlargements of the radiographs were made.

[The femoro-patellar joint and cartilage damage of the knee joint].

This article surveys the update knowledge of diagnosis and treatment of damage to the cartilage with particular reference to the femoropatellar joint. Complementary to this the biomechanical fundamentals and special anatomic features are explained, the knowledge of which is imperative for an understanding of the complex linkups and interconnections.

Cell volume regulation in liver.

The maintenance of liver cell volume in isotonic extracellular fluid requires the continuous supply of energy: sodium is extruded in exchange for potassium by the sodium/potassium ATPase, conductive potassium efflux creates a cell-negative membrane potential, which expelles chloride through conductive pathways. Thus, the various organic substances accumulated within the cell are osmotically counterbalanced in large part by the large difference of chloride concentration across the cell membrane. Impairment of energy supply leads to dissipation of ion gradients, depolarization and cell swelling.

Synthetic pentapeptide from the B1 chain of laminin promotes B16F10 melanoma cell migration.

Laminin is a basement membrane-specific glycoprotein that promotes cell adhesion, proliferation, differentiation, and tumor cell migration. Synthetic peptides from the amino acid sequence deduced from a cDNA clone of the B1 chain of laminin were tested for their ability to promote the migration of B16F10 melanoma cells. A peptide, CDPGYIGSR, that is able to mediate epithelial cell attachment to laminin was found to promote migration, and the constituent pentapeptide YIGSR was also active but to a lesser degree.

YIGSR, a synthetic laminin pentapeptide, inhibits experimental metastasis formation.

The invasion of tumor cells through basement membranes is a critical step in the formation of metastases. The binding of the malignant cells to laminin in the basement membranes allows their attachment and activates their invasiveness. Recently a synthetic nonapeptide from the B1 chain sequence of laminin was identified as a major site for cell binding.

A pentapeptide from the laminin B1 chain mediates cell adhesion and binds the 67,000 laminin receptor.

Laminin promotes epithelial cell adhesion in part through a site of nine amino acids CDPGYIGSR on the B1 chain. Using smaller synthetic peptides from this sequence as well as various peptides with amino acid substitutions, we find that the minimum sequence necessary for efficient cell adhesion as well as receptor binding is YIGSR. The deletion of tyrosine or the substitution of arginine in the peptides resulted in a significant loss of activity.

Identification of an amino acid sequence in laminin mediating cell attachment, chemotaxis, and receptor binding.

We have probed for active sites in the B1 chain of laminin using synthetic peptides comprising certain regions of its amino acid sequence as deduced from cDNA clones. An antibody to a 19-mer from domain III inhibited attachment of HT-1080 and CHO cells to laminin, while the peptide itself was inactive. A nearby peptide (CDPGYIGSR) from domain III with homology to epidermal growth factor was synthesized and found to be one of the principle sites in laminin mediating cell attachment, migration, and receptor binding.