A general synthetic route to a novel type of triamino-substituted planar carbenium ions (5) is reported. The synthetic method is based on a facile and selective nucleophilic aromatic substitution on the tris(2,4,6-trimethoxyphenyl)carbenium ion (1) with amines and gives access to a wide variety of more complex aminosubstituted carbenium ions. X-ray crystallography shows that the 2,6,10-tris(N-pyrrolidinyl)-4,8,12-trioxatriangulenium ion (5b) is planar and forms segregated stacks of cations and PF 6 anions in the solid phase. The stability of the 2,6,10-tris(diethylamino)-4,8,12-trioxatriangulenium ion 5a is expressed as the pK R+ value, which is determined in strongly basic nonaqueous solution on the basis of a new acidity function C_. The pK R+ value of 5a is measured to be 19.7, which is 10 orders of magnitude higher than the values found for the most stable carbenium ions previously reported. Electrochemical reduction of compound 5a leads to rapid dimerization. Two consecutive one-electron oxidations are identified by cyclic voltammetry.

In search for matrix proteins released from secretory vesicles of human neutrophils, a prominent 67-kD protein was identified in the extracellular medium of neutrophils stimulated by the chemotactic peptide, FMLP. The protein was purified to apparent homogeneity and partially sequenced. The sequence of the first 32 NH2-terminal amino acids was identical to the sequence of albumin. mRNA for human albumin could not be detected in bone marrow cells, nor could biosynthetic labeling of albumin be demonstrated in bone marrow cells during incubation with I14Clleucine.Immunofluorescence studies on single cells demonstrated the presence of intracellular albumin in fixed permeabilized neutrophils. Light microscopy of immunogold-silver-stained cryosections visualized albumin in cytoplasmic "granules." The morphology of these was determined by immunoelectron microscopy as vesicles of varying form and size. Subcellular fractionation studies on unstimulated neutrophils demonstrated the presence of albumin in the low density pre--y and Py-regions that contain secretory vesicles, but are devoid of specific granules and azurophil granules. Albumin was readily released from these structures during activation of neutrophils with inflammatory mediators. Immunoblotting demonstrated the presence of immunoglobulin and transferrin along with albumin in exocytosed material from stimulated neutrophils. This indicates that secretory vesicles are unique endocytic vesicles that can be triggered to exocytose by inflammatory stimuli. (J. Clin. Invest. 1992. 90:86-96.)

The reduction of aryl halides in the presence of stoichiometric amounts of carbon dioxide and catalytic amounts of PdnCl2(PPh3)2 has been previously reported to result in the formation of the corresponding carboxylic acids. It is shown here that the mechanism proceeds via a catalytic cycle initiated by the one-step, two-electron reduction of the divalent palladium complex followed by oxidative addition of the aryl halide to the resulting poorly ligated zerovalent palladium center "Pd°(PPh3)2", to afford the corresponding o-arylpalladium(II) intermediate. One-step, two-electron reduction of the latter yields an anionic o-arylpalladium(O), ArPd°(PPh3)2', which reversibly dissociates to restore the low-ligated zerovalent palladium complex, "Pd°(PPh3)2", while producing a free -aryl anion, Ar~. Nucleophilic attack of carbon dioxide by the latter yields the carboxylate derivative, ArCOf, while oxidative addition of the aryl halide to "Pd°(PPh3)f completes the catalytic cycle. It is thus concluded that the palladium-catalyzed carboxylation proceeds only through the involvement of diamagnetic palladium-centered intermediates, in contradiction with what has been established previously for the nickel catalysis of the same reaction.

The traditional classification of neutrophil granules as peroxidase‐positive (azurophil, or primary) and peroxidase‐negative (specific or secondary) has proven to be too simple to explain the differential exocytosis of granule proteins and incorporation of granule membrane into the plasma membrane which is an important aspect of neutrophil activation. Combined subcellular fractionation and immunoelectron microscopy has revealed heterogeneity among both peroxidase‐positive and peroxidase‐negative granules with regard to their content, mobilization and time of formation. Peroxidase‐negative granules may be classified according to their content of lactoferrin and gelatinase: 15% of peroxidase‐negative granules contain lactoferrin, but no gelatinase. 60% contain both lactoferrin and gelatinase. The term specific or secondary granule should be reserved for these two subsets. In addition, 25% of peroxidase‐negative granules contain gelatinase but no lactoferrin. These should be termed gelatinase granules or tertiary granules. Gelatinase granules are formed later than specific granules and mobilized more readily. In addition, a distinct, highly mobilizable intracellular compartment, the secretory vesicle, has now been recognized as an important store of surface membrane‐bound receptors. This compartment is formed in band cells and segmented cells by endocytosis. This heterogeneity among the neutrophil granules is of functional significance, and may also be reflected in the dysmaturation which is an important feature of myeloproliferative and myelodysplastic disorders.