Leon L. Miller

Bio: Leon L. Miller is an academic researcher from University of Rochester. The author has contributed to research in topics: Blood proteins & Blood plasma. The author has an hindex of 32, co-authored 120 publications receiving 4080 citations. Previous affiliations of Leon L. Miller include Kettering University.

The dominant role of the liver in plasma protein synthesis; a direct study of the isolated perfused rat liver with the aid of lysine-epsilon-C14.

Abstract: A direct study of the isolated rat liver perfused with oxygenated blood containing amino acids and lysine-epsilon-C(14) has yielded facts indicating that the liver synthesizes practically all the plasma fibrinogen, the albumin fraction, and probably more than 80 per cent of the plasma globulin fraction. The response of the isolated perfused liver in protein synthesis is qualitatively and quantitatively analogous to that of the intact animal, notably in (a) the ability to discriminate between natural L-lysine and D-lysine, (b) the per cent of isotopic amino acid converted to CO(2), (c) the per cent utilized in liver and plasma protein synthesis. The results obtained with the perfused liver are compared and contrasted with those reported for tissue homogenates, minces, and slices.

SYNTHESIS OF ALL PLASMA PROTEIN FRACTIONS EXCEPT GAMMA GLOBULINS BY THE LIVER THE USE OF ZONE ELECTROPHORESIS AND LYSINE-ϵ-C14 TO DEFINE THE PLASMA PROTEINS SYNTHESIZED BY THE ISOLATED PERFUSED LIVER

Abstract: Lysine-epsilon-C(14)-labeled plasma proteins produced by the normal rat and the isolated perfused rat liver have been fractionated by preparative zone electrophoresis. The isolated perfused liver incorporates lysine-epsilon-C(14) into the plasma albumin, alpha globulin, and beta globulin (including fibrinogen) fractions. No significant C(14) incorporation into the trichloracetic acid-precipitable proteins of the gamma globulin fraction was observed. Presumptive evidence indicates that the alpha globulins turn over more rapidly than any other major plasma protein fraction. The increased production of gamma globulins in liver disease is discussed.

Preparation of isolated rat liver cells.

Abstract: Publisher Summary This chapter discusses preparation of isolated rat liver cells The early mechanical and chemical methods for liver-cell preparation were relatively successful in converting liver tissue to a suspension of isolated cells The successful preparation of intact liver cells by perfusion with collagenase is technically quite difficult The major method for preparation of nonparenchymal liver cells is based on the selective sensitivity of parenchymal cells toward proteases By incubation of rat liver minces with pronase, most of the liver parenchyma is digested, while nonparenchymal cells remain intact and can be recovered from the incubate Similar results have been reported with trypsin digestion of collagenase-dispersed liver minces, but pronase appears to be more effective The most common procedure is to perfuse the liver briefly with pronase before it is minced and incubated with the enzyme Such direct pronase methods have been used by several investigators with yields of nonparenchymal liver cells reported to be in the range 2–15 × 10 6 cells/gm liver

HIGH-YIELD PREPARATION OF ISOLATED RAT LIVER PARENCHYMAL CELLS: A Biochemical and Fine Structural Study

Abstract: A new technique employing continuous recirculating perfusion of the rat liver in situ, shaking of the liver in buffer in vitro, and filtration of the tissue through nylon mesh, results in the conversion of about 50% of the liver into intact, isolated parenchymal cells. The perfusion media consist of: (a) calcium-free Hanks' solution containing 0.05% collagenase and 0.10% hyaluronidase, and (b) magnesium and calcium-free Hanks' solution containing 2 mM ethylenediaminetetraacetate. Biochemical and morphologic studies indicate that the isolated cells are viable. They respire in a medium containing calcium ions, synthesize glucose from lactate, are impermeable to inulin, do not stain with trypan blue, and retain their structural integrity. Electron microscopy of biopsies taken during and after perfusion reveals that desmosomes are quickly cleaved. Hemidesmosome-containing areas of the cell membrane invaginate and appear to pinch off and migrate centrally. Tight and gap junctions, however, persist on the intact, isolated cells, retaining small segments of cytoplasm from formerly apposing parenchymal cells. Cells which do not retain tight and gap junctions display swelling of Golgi vacuoles and vacuoles in the peripheral cytoplasm. Cytoplasmic vacuolization in a small percentage of cells and potassium loss are the only indications of cell injury detected. By other parameters measured, the isolated cells are comparable to normal hepatic parenchymal cells in situ in appearance and function.

Interleukin-6 and the acute phase response

Abstract: systemic reaction characterized by fever, leukocytosis, increase in erythrocyte sedimentation rate, increases in Leucocytosis secretion of ACTH and glucocorticoids, activation of Complement activat complement and clotting cascades, decreases in serum levels of iron and zinc, a negative nitrogen balance, and by dramatic changes in the concentration of some plasma ,l' proteins. These proteins are named acute phase proteins. i

Specific Proteolytic Cleavage of Poly(ADP-ribose) Polymerase: An Early Marker of Chemotherapy-induced Apoptosis

Abstract: Apoptosis is a morphologically and biochemically distinct form of cell death that occurs under a variety of physiological and pathological conditions. In the present study, the proteolytic cleavage of poly(ADP-ribose) polymerase (pADPRp) during the course of chemotherapy-induced apoptosis was examined. Treatment of HL-60 human leukemia cells with the topoisomerase II-directed anticancer agent etoposide resulted in morphological changes characteristic of apoptosis. Endonucleolytic degradation of DNA to generate nucleosomal fragments occurred simultaneously. Western blotting with epitope-specific monoclonal and polyclonal antibodies revealed that these characteristic apoptotic changes were accompanied by early, quantitative cleavage of the M(r) 116,000 pADPRp polypeptide to an M(r) approximately 25,000 fragment containing the amino-terminal DNA-binding domain of pADPRp and an M(r) approximately 85,000 fragment containing the automodification and catalytic domains. Activity blotting revealed that the M(r) approximately 85,000 fragment retained basal pADPRp activity but was not activated by exogenous nicked DNA. Similar cleavage of pADPRp was observed after exposure of HL-60 cells to a variety of chemotherapeutic agents including cis-diaminedichloroplatinum(II), colcemid, 1-beta-D-arabinofuranosylcytosine, and methotrexate; to gamma-irradiation; or to the protein synthesis inhibitors puromycin or cycloheximide. Similar changes were observed in MDA-MB-468 human breast cancer cells treated with trifluorothymidine or 5-fluoro-2'-deoxyuridine and in gamma-irradiated or glucocorticoid-treated rat thymocytes undergoing apoptosis. Treatment with several compounds (tosyl-L-lysine chloromethyl ketone, tosyl-L-phenylalanine chloromethyl ketone, N-ethylmaleimide, iodoacetamide) prevented both the proteolytic cleavage of pADPRp and the internucleosomal fragmentation of DNA. The results suggest that proteolytic cleavage of pADPRp, in addition to being an early marker of chemotherapy-induced apoptosis, might reflect more widespread proteolysis that is a critical biochemical event early during the process of physiological cell death.

Studies on antibody production i. a method for the histochemical demonstration of specific antibody and its application to a study of the hyperimmune rabbit

Abstract: A method for the specific histochemical demonstration of antibody in cells and parts of cells is described. It consists of carrying out a two stage immunological reaction on frozen sections of tissues: (a) allowing reaction between antibody in the tissue and dilute antigen applied in vitro, and (b) the detection of those areas where this antigen has been specifically absorbed by means of a precipitin reaction carried out with fluorescein-labelled antibody. Examination under the fluorescence microscope reveals the yellow-green fluorescence of fluorescein over those areas where a precipitate has formed. A study of the hyperimmune rabbit on the first few days after the last of a series of intravenous antigen injections reveals that antibody against human gamma-globulin or ovalbumin is present in groups of plasma cells in the red pulp of the spleen, the medullary areas of lymph nodes, the submucosa of the ileum, and the portal connective tissue of the liver. Because of extensive non-specific reactions, the bone marrow could not be examined. Small amounts of antibody were occasionally visible in cells in the lymphoid follicles of the spleen and lymph nodes, so that a minor contribution by lymphocytes to antibody synthesis cannot be excluded.