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E Reich

Publications and source records attributed to E Reich.

At least 127 records · Page 7Linked to original sources
PubMed1982

A proenzyme form of human urokinase.

A culture of the human epidermoid carcinoma HEp 3 produces a plasminogen activator of Mr = 53,000 which we have purified to apparent homogeneity from serum-free conditioned medium by the combination of immunoaffinity chromatography and preparative sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The highly purified protein has the following properties: 1) It is indistinguishable from urinary urokinase in electrophoretic mobility, in immunodiffusion, and in autoradiographically visualized tryptic peptide maps obtained from the 125I-labeled proteins. 2) The HEp 3 protein differs from urinary urokinase in the following respects: (a) although the apparent molecular weights of the two are identical (Mr = 53,000), the urinary enzyme consists of two polypeptide chains, whereas the HEp 3 protein is a single chain form. (b) Urinary urokinase can be labeled easily by incubation with radioactive diisopropylfluorophosphate but the HEp 3 protein cannot. (c) When assayed by the hydrolysis of a synthetic chromogenic peptide substrate, the HEp 3 enzyme has less than 1% of the catalytic activity of urinary urokinase. 3) On controlled exposure to plasmin, the HEp 3 protein is converted to an active enzyme that is identical with urinary urokinase in molecular weight, polypeptide chain composition, diisopropylfluorophosphate labeling, and specific catalytic activity. We conclude that the HEp 3 protein is a proenzyme that can be converted to active two-chain urokinase by plasmin, probably by a single proteolytic nick in the polypeptide chain.

Carcinoma, Squamous Cell↗
PubMed1982

Isolation and characterization of urokinase from human plasma.

The presence of activators of the fibrinolytic system in blood plasma has been assumed for a long time but never convincingly documented by the isolation of characterized and physiologically plausible enzymes. The low catalytic efficiency of previously identified plasma plasminogen activators, which has made their physiological significance uncertain, prompted us to search for other plasma enzymes, resembling especially the potent urinary activator, urokinase. We report here the detection of a urokinase-like activity in human plasma, and the isolation of the enzyme from whole plasma protein fractions. The purified enzyme is indistinguishable from the 53,000-dalton components of human urinary urokinase in the following respects: apparent Mr on sodium dodecyl sulfate-polyacrylamide gel electrophoresis, double immunodiffusion, amino acid analysis, two-dimensional tryptic peptide maps, catalytic efficiency with synthetic peptide substrates, and inhibitor spectrum. The results suggest (a) that the enzyme is present in plasma in a latent form whose nature remains to be defined, and (b) that the circulating concentration is at least 5 to 10 microgram/liter, and sufficient to generate substantial levels of plasmin, particularly if activation were somehow confined by localization at specific sites.

Amino Acids↗
PubMed1982

Acetylcholine receptor: effects of proteolysis on receptor metabolism.

Previous studies (Miskin, R., T. G. Easton, and E. Reich, 1970, Cell. 15:1301-1312) have shown that sarcoma virus transformation and tumor promoters reduced the cell surface concentration of acetylcholine receptors (AChR) in differentiating chick embryo myogenic cultures. Both of these agents also induced high rates of plasminogen activator (PA) synthesis in myogenic cultures (Miskin, R., T. G. Easton, A. Maelicke, and E. Reich, 1978, Cell. 15:1287-1300), and the present work was performed to establish whether proteolysis might significantly affect receptor metabolism. Proteolysis in myogenic cultures was modulated by one or more of the following: stimulation of PA synthesis, direct addition of plasmin, removal of plasminogen, or addition of plasmin inhibitors. The results were: (a) When the rates of proteolysis were raised either by addition of plasmin or by stimulating PA synthesis in the presence of plasminogen, both the steady-state concentration and the half-life of surface AChR decreased, but the rate of receptor synthesis was unaffected. (b) The magnitude of these effects, and their dependence on added plasminogen, indicated that proteolysis initiated by plasminogen activation could account almost entirely for the reduction in receptor half-life produced by sarcoma virus transformation and phorbol ester. (c) The rate of receptor synthesis, which is also reduced by viral transformation and tumor promoters, was not modified by proteolysis; hence plasmin action may be responsible for a large part, but not all of the change in surface receptor under these conditions. (d) The plasmin catalysed changes in receptor parameters appear to occur in response to modified membrane metabolism resulting from proteolysis of surface components other than AChR itself.

Animals↗
PubMed1982

GTG banding is not sufficient for the localization of breakpoints in translocations.

This study demonstrated that the GTG banding technique is not sufficient for the precise localization of breakpoints in translocations. Multiple banding techniques are required in cases with complex rearrangements before describing a so called "new syndrome'. Nevertheless, it is concluded that each banding technique has certain advantages, but GTG technique is the poorest choice.

Adult↗
PubMed1981

Plasminogen in the chick embryo. Transport and biosynthesis.

As part of a program to define potential roles for plasminogen activation during development, we have studied the metabolism of plasminogen in the chick embryo. Here we report that: 1) plasminogen is present in significant quantities in the yolk of fertile, unincubated eggs; 2) the zymogen can be translocated intact, from the yolk to the developing embryonic circulation; and 3) de novo synthesis of plasminogen occurs during the early phases of embryonic life. The combination of a reservoir of the zymogen in the yolk and protein biosynthesis thus ensures the availability of a substrate for enzymes which may participate in morphogenetic events occurring throughout embryonic life.

Animals↗
PubMed1981

Induction of plasminogen activator synthesis by antibodies.

We have purified the immunoglobulins (IgG) from rabbit antisera raised against two cell lines--LLC-PK1 derived from pig kidney and from Kirsten sarcoma virus-transformed BALB/3T3--and have studied the effects of IgG on cultures of the respective target cells. The following observations were made with both cell types: (a) The addition of purified IgG produced a rapid change in morphology within 2 h. This consisted of cell rounding, agglutination, and detachment from the surface of the dish. (b) Beginning approximately 2 h after IgG addition there was a progressive rise in plasminogen activator production for 24--36 h. (c) Both the morphological change and the induction of plasminogen activator (PA) synthesis were reversible and required the continued presence of IgG for their maintenance. The increase in PA production, but not morphological change, depended on genetic transcription and translation, being inhibited by actinomycin and/or cycloheximide. (d). These effects of IgG were specific: they were not observed with preimmune or indifferent IgG and occurred only after interaction between an IgG preparation from antisera and the cells used to generate the particular antiserum. The divalent IgG fragments F(ab')2 retained fully the activities of the native IgG molecules from which they were derived.

Animals↗
PubMed1981

Purification of murine T cell growth factor. A lymphocyte mitogen with helper activity.

Mouse T cell growth factor was purified from the serum-free conditioned medium of lectin-stimulated spleen cells. A 3,000-fold purification was achieved with a final yield of 12%. The purified protein, with an apparent Mr of 23,000 by sodium dodecyl sulfate polyacrylamide gel electrophoresis, was active at concentrations of 4 x 10(-11) M, both in the T cell growth factor and T cell replacing factor assays. In addition, purified T cell growth factor alone was mitogenic for spleen cells from both nude and normal mice.

Animals↗
PubMed1981

Plasminogen activator in the bursa of Fabricius: correlations with morphogenetic remodeling and cell migrations.

The association of controlled extracellular proteolysis, mediated by plasminogen activator, with embryonic tissue remodeling and cell migration was studied in the developing bursa of Fabriculus of quail and chick embryos. We found: that the specific activity of plasminogen activator in the bursa changes as a function of developmental age; that these changes are correlated temporally with the migration of hemopoietic cells into the bursal rudiment and with the period of extensive remodeling in the bursal epithelium; that the enzyme is distributed asymmetrically in the epithelial and mesenchymal compartments of the bursa. Chick and quail plasminogen activators can be distinguished by differences in their rates of electrophoretic migration. When interspecific grafts between quail and chick embryos were analyzed in this way, we observed that hemopoietic precursor cells produce plasminogen activator during their colonization of the bursa.

Animals↗
PubMed1981

Calcitonin stimulates plasminogen activator in porcine renal tubular cells: LLC-PK1.

Plasminogen activators are highly selective proteases that activate the proenzyme plasminogen to the general protease, plasmin. We studied a porcine kidney cell line, originally isolated as a high producer of plasminogen activator, in which activities of cellular adenylate cyclase and cAMP-dependent protein kinase are increased in response to calcitonin. We found that salmon calcitonin, in the concentration range 0.03-300 nM, increased plasminogen activator production up to approximately 1,000-fold and concurrently inhibited cell multiplication; both of these effects were reversible. Human calcitonin was approximately 0.01 times as potent as salmon calcitonin, corresponding to potency differences observed in other biological systems. Plasminogen activator production was also stimulated by other agents that raise cellular cAMP levels such as cholera toxin, phosphodiesterase inhibitors, and vasopressin, but not to the same extent as by calcitonins. The rapidity and sensitivity of the plasminogen activator determination and other cellular responses may make it possible in the future to use this cell stain in a convenient bioassay for calcitonins and their analogues.

Animals↗
PubMed1981

Plasminogen activator: analysis of enzyme induction by ultraviolet irradiation mapping.

Ultraviolet irradiation mapping techniques have previously been used to study the organization of eucaryotic gene classes and transcription units. We used the same method to probe some regulatory phenomena observed in the induction of plasminogen activator (PA) biosynthesis: PA synthesis in chicken embryo fibroblasts is induced by tumor-promoting phorbol esters and by retinoic acid; furthermore, PA induction by phorbol esters is synergistic with transformation, being 10- to 20-fold greater in virus-transformed cells than in normal cells. We found that the ultraviolet irradiation inactivation cross sections for PA induction by phorbol esters and by retinoate differed significantly, suggesting that these agents induce PA biosynthesis by different mechanisms. On the other hand, the ultraviolet irradiation sensitivity of phorbol ester induction in normal chicken embryo fibroblasts was the same as in transformed cells, indicating that the synergism of transformation and phorbol esters is probably not due to different pathways of PA induction.

Animals↗
PubMed1980

Long-term energy savings hospital's goal.

Using cost/benefit analysis, this hospital has implemented a variety of cost-effective energy conservation projects and is looking into long-term programs for the future.

Conservation of Energy Resources↗
PubMed1980

The culture of hormone-dependent epithelial cells from the rat ventral prostate.

This paper describes a method for obtaining cultures of rat ventral prostate epithelial cells. The prostate is first perfused with a collagenase solution before removal from the animal; subsequent mincing and incubation in vitro produces a suspension of alveolar cell clumps. Upon incubation, these clumps attach to the surface of the culture dish and spread into discrete epithelial cell colonies, which both retain differentiated morphology, and secrete a species of plasminogen activator that is characteristic of prostatic tissue. These properties were not observed in cultures prepared from single cell suspensions of the same organ. Maintenance of epithelial colony integrity and secretory activity specifically required the continued presence of stromal cells, glucocorticoids and insulin. Androgenic steroids were much less effective than glucocorticoids in stimulating plasminogen activator secretion and in maintaining colony integrity, in spite of the well-established androgen dependence of prostatic tissue morphology in vivo and in organ culture. Furthermore, no effects of prolactin were observed, either when this hormone was tested alone or in conjunction with steroid hormones. Of 3 retinoids tested, retinal was highly cytotoxic at concentrations in the range of 1 microM, whereas retinol and retinoic acid were without detectable effect.

Animals↗
PubMed1980

An improved assay for interleukin 2 (lymphocyte growth factor) produced by mitogen-activated lymphocytes.

The continued proliferation of activated T cells requires the presence of a lymphocyte growth factor in the culture medium. This study describes a rapid, highly reproducible assay to quantitatively measure levels of this lymphokine. The use of Concanavalin-A blast cells given this assay a high degree of flexibility and convenience. It is shown that the lymphokine measured is interleukin 2. The presence of an inhibitor in the supernatant of mitogen activated lymphocytes and the species specificity of the factor are demonstrated.

Animals↗
PubMed1980

Plasminogen activator of islets of Langerhans: modulation by glucose and correlation with insulin production.

Islets of Langerhans isolated from rat pancreas contain and secrete plasminogen activator (PA). Production of PA is increased up to 15-fold by culture in the presence of high concentrations of glucose, and the dose-response curves for the effect of glucose on secretion of PA and on insulin are superimposable. Alloxan, a diabetogenic agent that is selectively cytotoxic for beta cells, abolishes the PA response to glucose. Various agents and hormones that affect beta-cell function affect the secretion of PA in a manner parallel to their modulation of insulin secretion. These observations suggest that PA is produced by beta cells and that enzyme synthesis and secretion are regulated in concert with those of the hormone. The potential role of PA and of plasmin in the physiology of the islets is considered. In particular, because plasmin cleaves proinsulin to a product that is electrophoretically indistinguishable from insulin, it is suggested that the PA/plasmin system may play a part in the conversion of proinsulin to the active hormone.

Alloxan↗
PubMed1980

Antibodies from myasthenic patients that compete with cholinergic agents for binding to nicotinic receptors.

We have purified immunoglobulins from sera of myasthenic patients and have identified antibodies directed against the cholinergic ligand-binding site of the nicotinic acetylcholine receptor. In the serum of one patient analyzed in detail these antibodies belonged to the IgG3 class, and their effects were as follows: (i) In chicken embryo myogenic cultures, antibody binding was both competitive with 125I-labeled alpha-bungarotoxin and irreversible on a time scale of hours. (ii) 125I-Labeled alpha-bungarotoxin was not displaced by antibody from preformed complexes and, conversely, antibody was not displaced by toxin. (iii) Antibody binding was competitive with some, but not all, nicotinic agents. Thus, acetylcholine, carbamoylcholine, and dimethyltubocurarine competed effectively whereas decamethonium and hexamethonium did not, suggesting that the two classes of nicotinic ligands probably interact at different, nonoverlapping receptor subsites. (iv) There was no competitive binding between these antibodies and the muscarinic antagonist atropine. (v) Both this class of myasthenic immunoglobulins and rabbit antibodies raised against Torpedo acetylcholine receptors increased the rate of receptor degradation. However, synthesis and degradation remained coupled and there was a compensating increase in receptor synthesis. We propose that immunoglobulins directed against the ligand-binding site of acetylcholine receptors may account for the characteristic curare-like symptoms of early myasthenia and their response to cholinesterase inhibition, for the apparent decrease in receptors measurable by 125I-labeled alpha-bungarotoxin binding, and for initiating localized complement activation at the postsynaptic membrane.

Animals↗