PubMed Health⌕ Search

Biomedical subjects

A M Dannenberg

Publications and source records attributed to A M Dannenberg.

At least 73 records · Page 4Linked to original sources
PubMed1975

Macrophage esterase: identification, purification and properties of a chymotrypsin-like esterase from lung that hydrolyses and transfers nonpolar amino acid esters.

A chymotrypsin-like esterase was purified from beef lung. This lysosomal enzyme, not previously characterized, seemed to be composed of two or more forms with molecular weights of about 52 000. It hydrolysed N-benzoyl-DL-phenylalanine beta-naphthol ester at acid and neutral pH; it polymerized L-phenylalanine methyl ester(Phe-OMe) at neutral pH; and it transferred the Phe-residue from Phe-OMe to hydroxylamine at neutral pH. Phenylmethanesulfonyl fluoride, an inhibitor of hydrolytic enzymes with serine in their catalytic site, inhibited this enzyme, but pepstatin, the cathepsin D (EC 3.4.4.23) inhibitor, did not. Sulfhydryl reagents were not required for activity. Macrophages, especially pulmonary alveolar macrophages, were a rich source of this esterase, so it is likely that the enzyme purified from lung came from its macrophages. The esterase hydrolysed and transferred monoamino acid esters, especially those of the aromatic type. Cathepsin C, the dipeptidyl peptide hydrolase (EC 3.4.14.1), acted only on dipeptide esters and amides. Pancreatic chymotrypsin acted on both monoamino acid and dipeptide esters. The chymotrypsin-like esterase did not hydrolyse hemoglobin, casein, or plasma albumin. Thus its proteolytic activity, if present, must be limited to specific substrates, as yet unknown.

Amino Acids↗
PubMed1975

Capillary density in developing and healing tuberculous lesions produced by BCG in rabbits. A quantitative study.

Dermal tuberculous lesions were produced in rabbits by the intradermal injection of BCG. At various times after infection, anesthetized animals were perfused with a gelatin-colloidal carbon medium via the abdominal aorta. The capillary density of the nonnecrotic granulation tissue in the lesions was determined quantitatively by counting the capillaries under an ocular grid of a microscope. The capillary density in normal skin near the lesions was 3.8 plus or minus 0.5 in millimetersof capillary lengths per square millimeter in 250-mu tissue sections. The capillary density of the nonnecrotic tissue in BCGlesions averaged 6.1 plus or minus 0.6 mm/sq mm, an increase of 60%. The capillary density remained more or less constant as the BCG lesions grew and then regressed. The development of delayed hypersensitivity seemed to increase the capillary density, but this increase may have been a response to an extension of the necrosis at the time delayed hypersensitivity developed. Capillary densities in tuberculin reactions resembled those in BCG lesions. In the early stages, the increaseed capillary network of dermal BCG lesions was derived mainly from the subpapillary vascular plexus of the deep dermis supplied branches that surrounded the lower half of the caseous necrotic center and anastomosed with capillaries from the subpapillary plexus supplying the upper half. When the necrotic center extended, nearby capillaries thrombosed and in turn became necrotic. Peripherally, new capillaries formed and anastomosed with existing capillaries. From these vessels, mononuclear phagocytes emigrated, destroyed the tubercle bacilli, and enabled the lesion to heal. In the BCG lesions at all stages of development and healing, the capillary network in the nonnecrotic areas seemed adequate to supply and nourish the defense cells controlling the infection.

Animals↗
PubMed1974

The role of cathepsin D in the pathogenesis of tuberculosis. A histochemical study employing unlabeled antibodies and the peroxidase-antiperoxidase complex.

Cathepsin D was visualized in free pulmonary alveolar macrophages (AM), in oil-induced peritoneal macrophages (MN) and in rabbit pulmonary and dermal BCG lesions with unlabeled antibodies and the peroxidase-antiperoxidase (PAP) complex. Large amounts of cathepsin D were present in AM and lower amounts in MN. In the lung this enzyme was richest in the alveolar macrophages that accumulated around the BCG lesions. In the dermal lesions, cathepsin D was in highest concentration in macrophages at the border of the necrotic (liquefying) centers. It was also found in high concentration in keratinizing cells of the dermal epithelium and hair follicles. It did not, however, increase appreciably in many of the activated macrophages that stained intensely for the lysosomal enzyme beta-galactosidase. In fact, many epithelioid cells with high beta-galactosidase activity contained no visible cathepsin D. This proteinase does not, therefore, seem to be primarily involved in the lymphocyte-mediated macrophage activation associated with acquired cellular resistance to tubercle bacilli. It is probably more involved with cell autolysis, with the digestion of ingested necrotic debris and, in all likelihood, with the process of liquefaction, the most adverse event in the pathogenesis of tuberculosis in man.

Animals↗
PubMed1973

Inhibition of cathepsin D-type proteinase of macrophages by pepstatin, a specific pepsin inhibitor, and other substances.

The macrophage is the main cell participating in chronic inflammation. It contains an acid-acting, cathepsin D-type proteinase with the specificity of pepsin, which may release mediators of the inflammatory process. To find new pharmaceutical inhibitors of this proteinase, we tested a variety of chemical compounds in vitro. For this survey, the possible inhibitor (at a concentration of 0.4 mg/ml) was assayed with partially purified cathepsin D-type proteinase from beef lung (a macrophage-rich tissue) and hemoglobin as the substrate. Diazophenylbutanone, three acetophenones, two barbiturates, a gold salt, a copper chelate of a substituted nicotinic acid, a hexapeptide containing a d-amino acid, and Pepstatin inhibited this enzyme; over 200 other potential inhibitors did not. By far the most active and specific inhibitor found to date is Pepstatin, a pentapeptide with two gamma-NH linkages, two beta-OH groups, and five branched aliphatic side chains. Banyu Pharmaceutical Co., Tokyo, Japan, produces this nontoxic compound for the treatment of peptic ulcers. In vitro, as little as 4 ng of Pepstatin inhibits the acid-acting cathepsin D-type proteinase purified from beef and rabbit lung as well as the similar proteinase of rabbit peritoneal and pulmonary macrophages.

Acetophenones↗
PubMed1973

Purification and properties of the cathepsin D types proteinase from beef and rabbit lung and its identification in macrophages.

The acid-acting proteinase, cathepsin D (EC 3.4.4.23), was purified from extracts of homogenized rabbit lung and beef lung by autolysis at acid pH, acetone and ammonium sulfate fractionation, column chromatography, and isoelectric focusing. Four isoenzymes were obtained from each source. With acid hemoglobin as the substrate, the proteinase from rabbit lung had a pH optimum of 3.0 and that from beef lung had a pH optimum of 3.6. Their activity was not affected by thiol reagents or by Fe(2+), Mn(2+), or Mg(2+). One isoenzyme from rabbit lung was used to immunize a goat, and one from beef lung was used to immunize a rabbit. In immunoelectrophoresis, each resulting antiserum formed a single precipitin line with its homologous enzyme. They cross-reacted with the other three isoenzymes from the same species, but not with any isoenzyme from the other species. At high concentrations, each antiserum completely inhibited the proteolytic activity of its homologous enzyme. The antiserum against rabbit lung cathepsin D also inhibited the proteolytic activity of rabbit peritoneal and pulmonary macrophages. In limited quantities, this antiserum has now been made commercially available and is being used with labeled antibody techniques to identify under a microscope the presence of cathepsin D in macrophages and to study its role in the pathogenesis of tuberculosis.

Acetone↗
PubMed1972

Macrophage accumulation, division, maturation, and digestive and microbicidal capacities in tuberculous lesions. I. Studies involving their incorporation of tritiated thymidine and their content of lysosomal enzymes and bacilli.

Dermal and pulmonary tuberculous lesions were produced in rabbits with BCG, biopsied, incubated in vitro with tritiated thymidine ((3)HT) under hyperbaric oxygen, quickly frozen, sectioned in a cryostat, stained for the lysosomal enzyme beta-galactosidase, autoradiographed, stained for acid-fast bacilli and counterstained with hematoxylin. As macrophages developed into epithelioid cells, they could still divide-ie, incorporate (3)HT. However, once they became fully mature epithelioid cells that were 4-plus in beta-galactosidase, they could not do so. Tuberclebacilli did not stimulate macrophage division. On the contrary, macrophages containing bacilli did not divide, except when the lesions began. During the development of tuberculous lesions, macrophages (including those rich in enzymes and those containing bacilli) died, forming caseous centers. Therefore, local cell division did not seem to be the main mechanism by which macrophages reduced their bacillary load. Such division seemed mainly to occur in young macrophages that had recently immigrated into the lesions from the bloodstream and had not yet ingested bacilli.

Animals↗
PubMed1971

Radiation, Infection, and Macrophage Function IV. Effect of Radiation on the Proliferative Abilities of Mononuclear Phagocytes in Tuberculous Lesions of Rabbits.

Rabbits were irradiated with 400 to 600 rads 2 to 3 days before they were infected with BCG or with virulent tubercle bacilli. Biopsies were periodically removed from the resulting lesions and incubated for 1 hr with (3)H-thymidine in vitro under hyperbaric oxygen. Twelve to 16 days after radiation there was a reduction in the percentage of mononuclear cells (macrophages and some lymphocytes) that had incorporated (3)H-thymidine in the lesions. At this time, the lesions of the irradiated group were smaller than those of controls. These results can be explained by the reduction in the number of new mononuclear cells that entered the lesions of the irradiated group and support the tenet that local mononuclear cell division occurs mainly in cells that have recently emigrated from the blood stream. An alternate, but less likely, explanation of these results would be that radiation caused the bone marrow to release a higher percentage of "defective" mononuclear cells that were unable to divide, i.e., incorporate (3)H-thymidine, in the lesions. The reduction produced by radiation in both local cell infiltration and local cell division would decrease the number of macrophages available to control the tuberculous infection in the host.

Journal Article↗