Localization of the transmembrane proteoglycan syndecan-4 and its regulatory kinases in costameres of rat cardiomyocytes: a deconvolution microscopic study.

Syndecan-4 (syn-4), a transmembrane heparan sulfate-containing proteoglycan, is unique among the four members of the syndecan family in its specific cellular localization to complex cytoskeletal adhesion sites, i.e., focal adhesions.

Cardiogel: a biosynthetic extracellular matrix for cardiomyocyte culture.

Tissue-cultured neonatal cardiomyocytes can be successfully maintained in culture on a variety of extracellular matrix components such as laminin, fibronectin, and interstitial collagens (Types I and III). In vivo, however, cardiomyocytes (as well as many other cells) exist in a highly complex extracellular matrix environment composed of, in addition to the above three components, other proteins, proteoglycans, and growth factors. We have developed a procedure for culturing cardiomyocytes on a naturally occurring complete extracellular matrix, Cardiogel.

Hypoxia-induced alterations in cytoskeleton coincide with collagenase expression in cultured neonatal rat cardiomyocytes.

Incubation of cultured neonatal rat cardiomyocytes in hypoxic conditions, mimicking the deprivation of O2 which occurs during in situ myocardial ischemia, leads to a progressive change in cardiomyocytes cytoskeletal components. Confocal scanning laser immunofluorescence microscopy (CSLIM) reveals that the typical striated costameric distribution of vinculin gradually disappears to be replaced by circular, vinculin-containing sarcolemmal rosettes. There is little change in distribution of vinculin in the focal adhesions or in the intercalated disks.

Cytoskeletal alterations in cultured cardiomyocytes following exposure to the lipid peroxidation product, 4-hydroxynonenal.

Damage to the cardiac myocyte sarcolemma following any of several pathological insults such as ischemia (anoxia) alone or followed by reperfusion (reoxygenation), is most apparent as progressive sarcolemmal blebbing, an event attributed by many investigators to a disruption in the underlying cytoskeletal scaffolding. Scanning electron microscopic observation of tissue cultured rat neonatal cardiomyocytes indicates that exposure of these cells to the toxic aldehyde 4-hydroxynonenal (4-HNE), a free radical-induced, lipid peroxidation product, results in the appearance of sarcolemmal blebs, whose ultimate rupture leads to cell death. Indirect immunofluorescent localization of a number of cytoskeletal components following exposure to 4-HNE reveals damage to several, but not all, key cytoskeletal elements, most notably microtubules, vinculin-containing costameres, and intermediate filaments.

Lectinocytochemical specificity in human eosinophils and neutrophils: a reexamination.

As with secretory granules in other cell types, many of the protein components that make up the cytoplasmic granules of human leukocytes are glycoproteins. It is not unexpected, therefore, that lectins specific for various carbohydrate moieties can be localized in these granules following appropriate protocols for specimen preparation and thin-section labeling. In this study, isolated human eosinophils and neutrophils were prepared for lectin-gold electron microscopic localization by procedures that involve no exposure to aqueous fixatives, buffers, or solvents (rapid cryofixation and molecular distillation drying), thus removing the potential problem of constituent extraction or translocation during so-called "wet chemical" processing.

Studies of the function and structure of in vitro propagated human granulocytes.

In our study, hematopoietic progenitor cells isolated from human umbilical cord blood were grown in an in vitro liquid culture system using the recombinant colony stimulating factors IL-3 plus granulocyte-macrophage colony-stimulatory factor (GM-CSF) or IL-3 plus granulocyte colony stimulating factor (G-CSF). The morphology and function of the cells produced were then studied, and it was demonstrated that continuous exposure to IL-3 plus GM-CSF produced predominantly eosinophilic granulocytes, whereas IL-3 plus G-CSF produced neutrophilic granulocytes. Cells from IL-3/GM-CSF cultures showed progressively increasing oxygen metabolism and locomotive capabilities over time, which became equivalent to peripheral blood neutrophils at wk 4 and 3, respectively.

An accurate temperature monitoring device for Balzers rotary cold tables.

In the Balzers rotary cold table, the recording thermocouple is located 45 mm below the specimen stage. As a result, there is inconsistency between the temperature indicated by the thermocouple gauge and the actual temperature of the specimen carrier. This inconsistency is most notable and can lead to problems when the cold table temperature is changed, such as during the procedure when fracturing at one temperature is followed by etching at a higher temperature.