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R L Baehner

Publications and source records attributed to R L Baehner.

At least 181 records · Page 10Linked to original sources
PubMed1976

The biochemical basis of nitroblue tetrazolium reduction in normal human and chronic granulomatous disease polymorphonuclear leukocytes.

Normal human polymorphonuclear leukocytes (PMN) placed in anaerobic chambers reaching pO2's of less than 5 mm Hg fail to generate O2-, iodinate ingested particles, and stimulate glucose-1-14C oxidation through the hexose monophosphate shunt. The observation that anaerobic cells are incapable of generating O2- or reducing nitroblue tetrazolium (NBT) to formazan supports the idea that NBT reduction in phagocytizing PMN is due exclusively to oxygen-dependent O2- generating oxidase which is deficient in chronic granulomatous disease leukocytes, despite their hyperphagocytic capacity.

Granulomatous Disease, Chronic↗
PubMed1976

Benign and malignant teratomas in children: analysis of 85 patients.

Teratomas were observed in 85 infants and children. Fifty-eight (68%) were girls and 27 (32%) boys. Site of origin was sacrococcygeal in 55 patients (64.8%), mediastinal in ten (11.7%), gonadal in ten (11.7%), presacral in four (4.8%), retroperitoneal in three (3.5%), and cervical in three (3.5%). Sixty-seven (78.8%) teratomas were benign and 18 (21.1%) malignant. Malignant tumors were noted in 11 of 55 sacrococcygeal (20%), two of ten mediastinal (20%), three of eight ovarian (37.5%), and both testicular lesions. Cervical, retroperitoneal, and presacral tumors were benign. Age at diagnosis (greater than 1 month), presence of symptoms (urinary and colonic obstruction), and serum positive for alpha fetoprotein were indicators of malignancy in sacrococcygeal cases. Age was not a factor for teratomas at other sites. Tumor size, presence of calcification, and gross appearance (cystic or solid) did not relate to the tumor's benign or malignant nature. Three of four presacral tumors were associated with anorectal anomalies. Operative resection is the treatment of choice. Four deaths were related to operative hemorrhage. Four of five survivors with malignant teratoma received radiation and chemotherapy. A more aggressive role for combined adjunctive measures is suggested in cases of malignancy.

Abdominal Neoplasms↗
PubMed1975

In vitro colony-forming characteristics of chronic granulocytic leukemia in childhood.

Peripheral blood from a child with adult-type (Philadelphia chromosome positive) chronic granulocytic leukemia was found to contain large numbers of cells capable of colony formation in tissue culture. The majority of the colonies contained granulocytic cells. The source of these granulocytic colonies was found in a population of myeloblasts, promyelocytes, and myelocytes which could be separated from the more mature granulocytic cells of the peripheral blood by sedimentation of the buffy coat on Ficoll-Hypaque. The predominance of granulocytic colonies is in contrast to our observations previously made on the peripheral blood of children with "juvenile" type(Ph1 chromosome negative)CGL in which large numbers of exclusively monocytic colonies were produced in tissue culture. These current studies, when interpreted in light of relevant clinical data, suggest that the "juvenile" and "adult" types of CGL represent two very different forms of chronic leukemia in childhood. The Ph1 chromosome negative form may be classified as a monocytic leukemia with a granulocytic component but the Ph1 chromosome positive adult form, even when it occurs in a child, appears to be a true granulocytic leukemia.

Cell Division↗
PubMed1975

The role of superoxide anion generation in phagocytic bactericidal activity. Studies with normal and chronic granulomatous disease leukocytes.

The capacity of human phagocytes to generate superoxide anion (O2-), a free radical of oxygen, and a possible role for this radical or its derivatives in the killing of phagocytized bacteria were explored using leukocytes from normal individuals and patients with chronic granulomatous disease (CGD). Superoxide dismutase, which removes O2-, consistently inhibited phagocytosis-associated nitroblue tetrazolium (NBT) reduction indicating the involvement of O2- in this process. Similarly, superoxide dismutase inhibited the luminescence that occurs with phagocytosis, implicating O2- in this phenomenon, perhaps through its spontaneous dismutation into singlet oxygen. Subcellular fractions from homogenates of both normal and CGD leukocytes generated O2- effectively in the presence of NADH as substrate. However, O2- generation by intact cells during phagocytosis was markedly diminished in nine patients with CGD. Leukocytes from mothers determined to be carriers of X-linked recessive CGD by intermediate phagocytic reduction of NBT elaborated O2- to an intermediate extent, further demonstrating the interrelationship between NBT reduction and O2- generation in phagocytizing cells. Activity of superoxide dismutase, the enzyme responsible for protecting the cell from the damaging effects of O2-, was approximately equal in homogenates of normal and CGD granulocytes. Polyacrylamide electrophoresis separated this activity into a minor band that appeared to be the manganese-containing superoxide dismutase associated with mitochondria and a more concentrated, cyanide-sensitive, cytosol form of the enzyme with electrophoretic mobility that corresponded to that of erythrocyte cuprozinc superoxide dismutase. Superoxide dismutase inhibited the phagocytic killing of Escherichia coli, Staphylococcus aureus, and Streptococcus viridans. A similar inhibitory effect was noted with catalase which removes hydrogen peroxide. Neither enzyme inhibited the ingestion of bacteria. Peroxide and O2- are believed to interact to generate the potent oxidant, hydroxyl radical (.OH). A requirement for .OH in the phagocytic bactericidal event might explain the apparent requirement for both O2- and H2O2 for such activity. In agreement with this possibility, benzoate and mannitol, scavengers of .OH, inhibited phagocytic bactericidal activity. Generation of singlet oxygen from O2- and .OH also might explain these findings. It would seem clear from these and other studies that the granulo cyte elaborates O2- as a concomitant of the respiratory burst that occurs with phagocytosis. To what extent the energy inherent in O2- is translated into microbialdeath through O2- itself, hydrogen peroxide, .OH, singlet oxygen, or some other agent remains to be clearly defined.

Catalase↗
PubMed1975

The role of superoxide anion and hydrogen peroxide in phagocytosis-associated oxidative metabolic reactions.

The contribution of hydrogen peroxide (H2O2) and one of its unstable intermediates, superoxide anion (O2), to the oxidative reactions that occur in phagocytizing leukocytes was explored by depleting these cells of O2. This was accomplished by allowing them to phagocytize latex particles coated with superoxide dismutase (SOD), which catalyzes the generation of H2O2 from O2. Although the rate and extent of phagocytosis of latex coated with bovine serum albumin was similar to latex coated with SOD, the rate of oxygen consumption, [14C]formate oxidation, [1-14C]glucose oxidation, and iodination of zymosan particles was significantly enhanced by SOD. In contrast, the rate and extent of reduction of nitroblue tetrazolium (NBT) was diminished by 60%. These studies indicate that the majority of NBT reduction by leukocytes is due to O2, whereas stimulation of the hexose monophosphate shunt and iodination of ingested particles requires H2O2 generated from the increased reduction of oxygen by phagocytizing leukocytes.

Anions↗
PubMed1975

Growth of rhabdomyosarcoma colonies from pleural fluid.

Pleural fluid from a child previously treated for rhabdomyosarcoma produced colonies in vitro. Cells from these colonies appeared to have the light and electron microscopic appearance of rhabdomyosarcoma cells. In this case, the malignant nature of the effusion had been suspected because of the patient's previous history; however, this technique may prove useful in the diagnosis of effusion of unknown etiology.

Animals↗
PubMed1975

Subcellular distribution of nitroblue tetrazolium reductase (NBT-R) in human polymorphonuclear leukocytes (PMN).

Subcellular distribution study of cytoplasmic organelles was performed on human polymorphonuclear leukocytes after homogenization in 0.34 molar sucrose by differential centrifugation and sucrose density gradient centrifugation of the homogenate. The whole homogenate and each fraction was assayed for nitroblue tetrazolium (NBT)-reductase with and without 1 mM potassium cyanide, and the distribution of this enzyme was compared to the distribution of lysozyme, peroxidase, beta-glucuronidase, and acid and alkaline phosphatase. Enzyme recovery was 97 per cent and ranged between 74 and 124 per cent. Latent activity of all enzymes except NBT-reductase, acid, and alkaline phosphatase was demonstrated by observing a four- to sixfold increase in activity after the addition of Triton-X 100. Maximal relative specific activity using either DPNH or without cyanide for NBT-reductase was found in the 100,000 x g differential centrifugation fraction and was concentrated in the less dense top fraction of the sucrose density gradient. The distribution pattern was similar to acid and alkaline phosphatase. In contrast, the maximal concentration of beta-glucuronidase and peroxidase was found in the heavier 7,200 x g granule fraction and in the more dense bottom fractions of the sucrose density gradient. Maximal lysozyme activity was concentrated in the 30,000 x g granule fraction and in the fractions located between the heaviest and lightest fractions of the sucrose density gradient. The lack of latent activity and the similarity of subcellular distribution of NBT-reductase to acid and alkaline phosphatase, two enzymes associated with microsomes and plasmalemal membranes in human polymorphonuclear leukocytes (PMN), indicates that NBT-reductase is also a nonlysosomal enzyme located in microsomes or in plasmalemal membranes. These findings support the previously described histochemical observations that initial reduction of NBT to formazan occurs on the PMN plasmalemal surface membrane at the point of particle attachment. In addition, they suggest that alteration of the surface membrane of the PMN by particle attachment or other surface forces may activate NBT-reductase, leading to an accumulation of formazan in the region of the altered membrane as the phagocytic vacuole is formed.

Acid Phosphatase↗
PubMed1975

Microbe ingestion and killing by neutrophils: normal mechanisms and abnormalities.

Microbial ingestion and killing by neutrophils involves the interaction between the phagocytic cells of the body and certain serum factors. The primary phagocytes of the blood are the polymorphonuclear neutrophil, eosinophil and monocyte. The fixed tissue macrophage of the reticuloendothelial system is responsible for phagocytosis and killing of encapsulated bacteria, viruses, and protozoans, whereas the blood phagocyte system is involved in killing of pyogenic bacteria and certain fungi. Proper ingestion of bacteria requires opsonisation of these bacteria by either complement of specific antibody, or an interaction of these two proteins. Opsonised bacteria are fixed to the surface of the phagocytic cells which contain receptors for IgG and C3. Following immune adherence ingestion of bacteria involves invagination of the plasmalemmal membrane. This process utilises ATP and a re-arrangement of lipids occurs during formation of the phagocytic vacuole. Granular enzymes containing peroxidase, hydrolases, and cationic proteins are transferred from the granule into the phagocytic vacuole. There is activation of oxidative metabolism with an increased consumption of oxygen leading to hydrogen peroxide production.

Anemia, Sickle Cell↗
PubMed1974

Lipid peroxidation in the killing of phagocytized pneumococci.

To directly examine the role of hydrogen peroxide in the killing of bacteria after ingestion by granulocytes, we have studied some of the events of phagocytosis of a mutant strain of pneumococci which is relatively deficient in peroxide production. The hydrogen peroxide-deficient pneumococci and the otherwise identical wild type were grown with [(14)C]arachidonic and [(3)H]palmitic acid labels to label their lipids with unsaturated and saturated fatty acids, respectively. They were then incubated with both normal and chronic granulomatous disease granulocytes. The rates of ingestion and bacterial killing and the stability of fatty acids in the cell-bacteria complex were followed. Radioactive carbon dioxide released from glucose was also independently followed to measure glucose oxidation. Ingestion was similar for all cell-bacteria combinations. Chronic granulomatous disease cells killed the peroxide-positive wild pneumococci much more effectively (20-fold) than the peroxide-deficient mutant. Normal cells killed both peroxide-positive and -negative strains effectively. A considerable loss of [(14)C]arachidonic acid ( approximately 40%) consistent with lipid peroxidation of this unsaturated fatty acid was observed in all normal cells and in chronic granulomatous disease cells with peroxide-positive pneumococci. However, no loss of [(14)C]arachidonic acid occurred in chronic granulomatous disease cells with the peroxide-deficient pneumococci. No loss tritiated palmitic acid occurred in any cell-bacteria combination. Glucose oxidation was impaired in the chronic granulomatous disease cells in comparison to normal cells at rest and was especially impaired in chronic granulomatous disease cells ingesting the peroxide-deficient mutant pneumococci. This defect was partially corrected after phagocytosis of the peroxide-positive strain. These data directly support the hypothesis that bacterial killing is partially dependent upon an intact peroxide-generating system in the leukocyte-bacteria complex. Moreover, they indicate that bacterial lipid peroxidation is associated with the generation of peroxide during phagocytosis. Finally, they suggest that such peroxidation may contribute to effective phagocytic bacterial killing.

Animals↗