Long term stimulation changes the vesicular monoamine transporter content of chromaffin granules.

Bovine chromaffin cells cultured for 5 days in the presence of depolarizing concentrations of K+ ions show a decreased number of secretory (chromaffin) granules per cell. These cells were still capable of exocytosis. Their contents in catecholamine and chromogranin A, components of the granule matrix, and cytochrome b561, a major protein of the granule membrane, were decreased to 35, 30, and 50% of control cells, respectively.

Expression of neural cell adhesion molecules, NCAMs, and their polysialylated forms, PSA-NCAMs, in the developing rat pituitary gland.

Neural cell adhesion molecules (NCAMs) can undergo post-translational modifications, such as the addition of polysialic acid chains, thus generating PSA-NCAMs, which are expressed mainly during development. Since polysialylation considerably modifies NCAM adhesivity, expression of NCAMs and PSA-NCAMs has been investigated in the developing hypophysis by immunohistochemistry. At embryonic day 13 (E13), an antibody against NCAM outlined all cellular profiles in the entire Rathke's pouch; this labelling persisted until adulthood.

Identification and characterization of a soluble c-kit receptor produced by human hematopoietic cell lines.

Stem cell factor (SCF) triggers cell growth by binding to cell surface c-kit receptors. Soluble forms of several cytokine receptors have been described and may play a role in the modulation of cytokine activity in vivo. For these reasons, we investigated whether human hematopoietic cells produce soluble c-kit receptors.

Spontaneous dissociation-association of monomers of the human-stem-cell-factor dimer.

In its native state, recombinant human-stem-cell-factor (SCF) dimer can spontaneously and rapidly undergo hybridization when two different SCF dimer species are incubated together. SCF species differing in molecular charge, e.g.

Soluble kit receptor in human serum.

c-kit encodes the transmembrane receptor tyrosine kinase (Kit) for the recently described ligand stem cell factor (SCF). We have developed an enzyme-linked immunosorbent assay for measuring soluble human Kit and we have used the assay to show high levels of soluble Kit in human serum. The distribution of soluble Kit levels was investigated among 112 normal human serum donors.

Computational analysis of non-Fourier motion.

Non-Fourier motion is now commonplace in research on visual motion perception, yet lacks a computational framework. This paper examines this issue based on the observation that many non-Fourier motion stimuli have a simple characterization in the frequency domain, in terms of oriented power distributions that lie along lines (or planes) that do not pass through the origin. This provides a unifying theoretical framework for a very diverse class of non-Fourier phenomena.

Expression of GAP-43 (neuromodulin) during the development of the rat adrenal gland.

The 'growth-associated protein', GAP-43 was originally considered to be a neuron-specific protein associated with plasticity. However, we have recently shown that GAP-43 is expressed by noradrenergic, but not by adrenergic chromaffin cells in the adult rat adrenal gland. In this study, we examine the expression of GAP-43 during embryonic and post-natal development of the adrenal gland using immunohistochemical techniques.

No effect of oral or sample temperature on sensory assessment of fat content.

This work examined the possible influences of oral and sample temperature on the perception of fat content of a model food system. Melting or related phenomena may contribute to the greater sensation of fat content and the highly acceptable textural characteristics associated with certain fats. Thirty-one adults assessed the fat content of 0%, 12%, 24%, 36%, and 48% oil-in-water emulsions prepared with a commercial cocoa butter substitute having a melting range of 17-41 degrees C.

Properties of variant forms of human stem cell factor recombinantly expressed in Escherichia coli.

The gene for human stem cell factor (SCF) encodes a leader sequence followed by 248 amino acids (Martin et al., 1990, Cell 63, 203). Of these 248 amino acids, the first 189 correspond to an extracellular domain and the remainder correspond to a hydrophobic transmembrane domain plus a cytoplasmic domain.

Sensory assessment of fat content: effect of emulsion and subject characteristics.

This work examines some of the fundamental stimulus properties contributing to the perception and discrimination of fat content in foods. In an initial experiment, oil-in-water (O/W) emulsions were prepared with 0, 5, 10, ..

Direct activation of human neutrophil procollagenase by recombinant stromelysin.

Human neutrophil procollagenase was activated by incubation with recombinant active stromelysin. Activation was achieved by cleavage of the Gly78-Phe79 peptide bond at the end of the propeptide domain in a single-step activation mechanism. In addition, accelerated activation was achieved when N-terminally truncated, latent collagenase (with Phe49 as its N-terminal residue) was incubated with recombinant active stromelysin.

Fragmentation of human polymorphonuclear-leucocyte collagenase.

Human polymorphonuclear-leucocyte collagenase (M(r) 64,000) shows autoproteolytic degradation to two major fragments of M(r) 40,000 and M(r) 27,000. N-terminal sequence data and investigation of the substrate specificity of the fragments demonstrate that the M(r)-40,000 fragment corresponds to the catalytic domain, whereas the M(r0-27,000 fragment shows no enzymic activity. The activity profile of the M(r)-40,000 fragment is comparable with the specificity of the intact active collagenase (M(r) 64,000), but the ability to cleave collagen was lost.

Rhinocerebral mucormycosis diabetes mellitus and adrenogenital syndrome.

A case of rhinocerebral mucormycosis in a diabetic is described. The case is unusual as the mucormycosis developed in the absence of ketoacidosis and because that patient had concomitant adrenogenital syndrome.

Melanoma-mediated dissolution of extracellular matrix: contribution of urokinase-dependent and metalloproteinase-dependent proteolytic pathways.

Constitutive overexpression of both urokinase and matrix metalloproteinase (MMP) activity is frequently observed in individual malignant tumors. In this study we describe the combined contribution of these distinct enzyme systems to the invasive phenotype of a highly metastatic human melanoma cell line (M24met). M24met cells were found to secrete a spectrum of MMPs, including interstitial collagenase, type IV collagenases (M(r) 92,000 and 72,000 progelatinases), and stromelysin.

Soluble stem cell factor in human serum.

Stem cell factor (SCF) is a recently described factor active in the early stages of hematopoiesis. It can exist in membrane-bound form and in proteolytically released soluble form. The levels and nature of SCF in human serum are described.

Characterization of the functional domain of tissue inhibitor of metalloproteinases-2 (TIMP-2).

Analysis of the functional domain of tissue inhibitor of metallo-proteinases-2 (TIMP-2) was performed using limited proteolytic degradation with trypsin. This treatment generated a 13.5 kDa fragment which was purified and shown to consist of an uncleaved N-terminal region extending from residue 1 to residue 132.

Isolation of rat bone marrow mast lineage cells using Thy 1.1 and rat stem cell factor.

Recent reports have shown that various marrow-derived cell populations respond vigorously to recombinant rat stem cell factor (rrSCF164), one form of the kit-ligand. In the present study, we isolated cell populations from rat bone marrow using the Thy 1.1 antigen (an antigen that in the rat is differentially expressed on primitive hemopoietic progenitor cells) and fluorescently conjugated rrSCF164 (rrSCF164-PE).

Cellular localization of the neural cell adhesion molecule L1 in adult rat neuroendocrine and endocrine tissues: comparisons with NCAM.

The tissue distribution and cellular localization of the neural cell adhesion molecule L1 was determined by immunocytochemistry at the optical and ultrastructural levels in adult rat neuroendocrine tissues and pancreatic endocrine cells. L1 was found to be abundant in the neurohypophysis but undetectable in the rest of the pituitary gland. It was barely detectable in the normal rat endocrine pancreas, but a rat pancreatic insulinoma cell line was found by immunofluorescence to express low levels of L1.

Expression of cell adhesion molecules and catecholamine synthesizing enzymes in the developing rat adrenal gland.

Cell adhesion molecules play a major role in determining tissue architecture during histogenesis. This immunocytochemical study of the adrenal gland examines the embryonic and early postnatal cellular expression of two neural cell adhesion molecules, NCAM and L1, which are widely expressed in brain and have been found also to be expressed in the adult rat adrenal gland. In parallel, antibodies directed against two neuroendocrine cell markers, tyrosine hydroxylase and phenylethanolamine N-methyltransferase, were employed to verify the phenotypic nature of developing chromaffin cells in order to correlate cell adhesion molecule expression with the state of chromaffin cell differentiation.