What is the difference between argentaffin and argyrophilic reactions? Both terms relate to the formation of colloidal metallic silver (latin argentum, Greek argyros) (1), which may range in color from yellow through brown to black depending on particle size and density, in specific structural components of tissues. the metal is formed at sites of reduction of silver ions derived from a stainin...

The remarkable increase in chondrocyte volume is a major determinant in the longitudinal growth of mammalian bones. To permit a detailed morphological study of hypertrophic chondrocytes using standard histological techniques, the preservation of normal chondrocyte morphology is essential. We noticed that during fixation of growth plates with conventional fixative solutions, there was a marked m...

Small strands and bundles of strands extend from the outside surface of suspension-cultured cells of Daucus, Ipomoea, and Phaseolus into the medium. This fibrous cell coat is present in all samples from various growth stages but appears to increase in quantity in the order Ipomoea < Phaseolus < Daucus. The bundles are often many microns in length and display great variation in frequency, size, ...

We have studied a series of three-way DNA junctions containing unpaired bases on one strand at the branch-point of the junctions. The global conformation of the arms of the junctions has been analysed by means of polyacrylamide gel electrophoresis, as a function of conditions. We find that in the absence of added metal ions, all the results for all the junctions can be accounted for by extended...

Secretory vesicles containing polysaccharide were isolated from germinated pollen of Lilium longiflorum and characterized by biochemical and ultrastructural investigation. Pollen tubes exhibit a secretory pathway in which the vesicles concentrated in the tube apex are produced by the Golgi apparatus and contributed to the cell wall at the apex upon fusion of the vesicle membrane with the plasma...

We synthesized a pentamine (3-3-3-3) and two hexamine (3-3-3-3-3 and 3-4-3-4-3) analogues of the natural polyamine, spermine (3-4-3) and studied their effectiveness in condensing pGL3 plasmid DNA, using light scattering and atomic force microscopic (AFM) techniques. The midpoint concentration of the polyamines on pGL3 condensation (EC50) was 11.3, 10.6, 1.5, 0.49 and 0.52 micro M, respectively,...

Knowledge of the relative stabilities of alane (AlH(3)) complexes with electron donors is essential for identifying hydrogen storage materials for vehicular applications that can be regenerated by off-board methods; however, almost no thermodynamic data are available to make this assessment. To fill this gap, we employed the G4(MP2) method to determine heats of formation, entropies, and Gibbs f...