Search PubMed⌕ Search

Biomedical subjects

R L Baehner

Publications and source records attributed to R L Baehner.

At least 55 records · Page 3Linked to original sources
PubMed1983

Abnormal distribution of complex carbohydrates in neutrophils of a patient with lactoferrin deficiency.

Previous studies have identified patients with susceptibility to bacterial infection associated with lactoferrin deficiency in dysmorphic neutrophils containing abnormal or no secondary granules and abnormal nuclear segmentation. We have investigated the subcellular distribution of vicinal glycol-containing complex carbohydrates in marrow and blood myeloid cells of such a patient using the periodic acid-thiocarbohydrazide-silver proteinate (PA-TCH-SP) staining method and have examined the response of these neutrophils to the degranulating agents N-formylmethionyl-leucyl-phenylalanine (FMLP) and phorbol myristate acetate (PMA). As in normal specimens, immature primary granules were strongly PA-TCH-SP reactive; however, unlike normal specimens, masking of PA-TCH-SP reactivity did not occur in mature primary granules. Endoplasmic reticulum demonstrated moderately strong PA-TCH-SP staining, in contrast to absent staining of this organelle in normal promyelocytes and consistent with abnormal primary granule genesis. Small abnormal elongated granules (0.1-0.2 micron in diameter) were identified at the myelocyte state of development and were the predominant granule type in late neutrophils. These granules were identified as secondary granules on the basis of their PA-TCH-SP positivity and were differentiated from primary and tertiary granules on the basis of a lack of peroxidase, acid phosphatase, and sulfate staining. When the neutrophils were exposed to PMA, cell aggregation occurred, and the abnormal granules degranulated in a manner similar to the degranulation observed with normal secondary granules. Although PA-TCH-SP staining of the plasma membrane appeared normal, a decrease in FMLP receptors was demonstrated. Thus, a defect(s) is present in complex carbohydrate distribution and staining that involves primary and secondary granules and possibly the plasmalemma of neutrophils from this patient. This results in abnormal packaging of primary granules and synthesis of normal numbers of secondary granules that are qualitatively and morphologically abnormal, but can be recruited to degranulate with PMA.

Acid Phosphatase↗
PubMed1983

Modulation of polymorphonuclear leukocyte function by cetiedil.

Cetiedil citrate monohydrate inhibits sickling of red cells and aggregation of platelets. We assessed its ability to attenuate polymorphonuclear leukocyte (PMN) function. PMN aggregation in response to 2 X 10(-7) M formyl-met-leu-phe (FMLP) was inhibited in a dose-dependent fashion by cetiedil concentrations ranging from 60 to 250 microM. Additionally, 125 microM cetiedil inhibited PMN aggregation in response to 2 X 10(-7) M FMLP, 20 ng/ml phorbol myristate acetate (PMA), and 1 X 10(-6) M A23187 by 69% +/- 18%, 72% +/- 20%, and 65% +/- 4%, respectively. Inhibition of FMLP-induced aggregation was provided by only 5 min of incubation of the drug with the cells and was partially reversible. Cell viability was unaffected by exposure of PMN to the drug. Correspondingly, 125 microM cetiedil prevented the translocation of calcium from the PMN membrane as assessed by chlorotetracycline fluorescence. Paralleling the effect of the drug on PMN aggregation, 125 microM cetiedil inhibited release of superoxide by 55% and decreased the number of available 3H-FMLP receptors. However, its effect on release of the primary granule constituent, myeloperoxidase, was minimal (4.5% inhibition), while the effect on release of the specific granule product, lactoferrin (27% inhibition), was modest. These studies indicate that cetiedil affects PMN aggregation and superoxide release to a much greater extent than PMN degranulation. Thus, cetiedil may have potential uses in modulating inflammatory response in vivo.

Azepines↗
PubMed1983

Comparative studies of functional characteristics of mononuclear cell subsets and granulocytes.

Two human peripheral blood monocyte subsets and lymphocytes were isolated by counterflow centrifugal elutriation (CCE). The cell volumes of 303 mu3 and 380 mu3 were measured for the smaller and larger monocyte populations, respectively. Superoxide release by large monocytes exposed to opsonized zymosan was five times more active than that of the small monocytes. The production of colony stimulating activity was two-fold greater and the myeloperoxidase activity was 1.4-fold greater by the larger monocytes. Enriched fractions of cytotoxic cells responsible for natural killer (NK) activity against neuroblastoma cells were also obtained by counterflow centrifugal elutriation. Natural killer cells were obtained in larger lymphocyte fractions and had a mean cell volume of 180 mu3. Compared with the NK activity against the neuroblastoma cells, both the small and large monocytes displayed greater antibody-dependent cellular cytotoxicity (ADCC) activity against human erythrocytes. The larger peripheral blood monocytes aggregated in response to FMLP (N-formyl-methionyl-leucyl-phenyl alanine peptide) and PAF (platelet activating factor). Unlike the granulocyte, monocyte aggregation in response to FMLP was not accompanied by degranulation nor was it potentiated by cytochalasin B. In addition, monocyte aggregation could be blocked by benoxaprofen, unlike the granulocyte. Thus, CCE provides a means of isolating subsets of monocytes and lymphocytes and obtaining large numbers of peripheral blood monocytes for functional studies.

Antibody-Dependent Cell Cytotoxicity↗
PubMed1983

The mechanism of action of the antiinflammatory agents dexamethasone and Auranofin in human polymorphonuclear leukocytes.

Human polymorphonuclear neutrophils (PMN) were treated with the antiinflammatory agents dexamethasone or Auranofin. PMN treated with dexamethasone in a dose range of 0.25-1 microM or Auranofin, 5-15 mM, were stimulated with 10(-7)M N-formyl-methionyl-leucyl-phenylalanine (FMLP). These agents were shown to inhibit the functional responses of degranulation and superoxide production in a dose-dependent manner. Similarly, the change in electrophoretic mobility, reflecting cell surface charge, was blocked. While both agents inhibited change in the fluorescence of the calcium chelate probe chlorotetracycline (CTC), the pattern of inhibition was significantly different. Dexamethasone appeared to inhibit the CTC response during its latter phases, while Auranofin inhibited all aspects of the CTC response. Auranofin was additionally shown to significantly decrease specific binding of FMLP, as well as the number of FMLP receptors. The two agents thus appear to act by different mechanisms. Dexamethasone is shown to have an effect on membrane-bound calcium release as measured by CTC, while Auranofin interferes with receptor binding.

Auranofin↗
PubMed1983

The comparative responses of human polymorphonuclear leukocytes obtained by counterflow centrifugal elutriation and Ficoll-Hypaque density centrifugation. I. Resting volume, stimulus-induced superoxide production, and primary and specific granule release.

Standard isolation techniques for the human polymorphonuclear leukocyte (PMN) involve sequential exposure of cells to the nonphysiologic environments of dextran, Ficoll-Hypaque (FH) gradient centrifugation, and hypotonic conditions. It has been suggested that these may be harmful to the recovered PMN. Counterflow centrifugal elutriation (CCE) allows separation of human PMNs while the cells are continuously bathed in a physiologic and isotonic buffer. To investigate whether preparative technique may alter PMN activation, we compared PMNs obtained by these two methods for stimulus-induced superoxide production and release of primary and specific granule contents. Resting PMN volume was also evaluated. We observed that PMNs obtained using the CCE method were larger and released significantly more superoxide and specific granule contents than PMNs obtained by the standard FH technique. The possible origins for these differences are discussed.

Adult↗
PubMed1983

Vitamin E--a selective inhibitor of the NADPH oxidoreductase enzyme system in human granulocytes.

The cellular sites of H2O2 formation in phagocytizing granulocytes have been identified with cerium chloride. A precipitate was visible in phagosomes and on plasma membranes from intact normal cells in the presence of either 0.71 mM NADH or NADPH. X-ray microanalysis permitted identification of cerium deposition within the phagosomes even in the absence of reduced pyridine nucleotides. Catalase ablated the formation of the reaction product. Intact granulocytes obtained from subjects receiving 1600 units of vitamin E daily for 2 weeks exhibited reaction product in the presence of NADH but not NADPH. Intact cells from subjects treated with vitamin E demonstrated diminished numbers of phagocytic vesicles containing reaction product. During phagocytosis the granulocytes treated with vitamin E consumed oxygen but exhibited significantly reduced rates of hydrogen-peroxide-dependent glucose-1-14C oxidation to 14CO2. Isolated phagocytic vesicles obtained from granulocytes after ingestion of opsonized lipopolysaccharide-paraffin oil droplets contained reaction product when exposed to 0.71 mM NADPH. No reaction product was evident at 0.71 mM NADH but was evident at 2.0 mM NADH. Isolated phagocytic vesicles from the granulocytes of subjects receiving vitamin E exhibited reaction product only in the presence of NADH. These observations suggest that vitamin E interferes with the electron transport chain apparently required for the oxidation of NADPH to form H2O2 in the phagocytizing granulocyte.

Cytochrome Reductases↗
PubMed1983

Synergistic effect of heparin and chemotactic factor on polymorphonuclear leukocyte aggregation and degranulation.

The in vitro effects of therapeutic amounts of polyanionic heparin on human polymorphonuclear leukocytes (PMN) aggregation and on the release of cationic lactoferrin from PMN-specific granules were investigated. Incubation of 1 X 10(7) human PMNs with 0.3 unit/ml of heparin followed by stimulation with the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (FMLP) 2 X 10(-7) M significantly increased PMN aggregation, compared with controls. Cytochalasin B potentiated aggregation, which was further increased by incubation of the PMNs with heparin. Similarly, heparin also increased PMN degranulation and lactoferrin release following stimulation with FMLP with or without cytochalasin B, compared with controls. In addition, human lactoferrin complexed with heparin on a sucrose density gradient and caused a significant shift in the migration of 3H-heparin. Finally, rabbits pretreated with intravenous heparin resulting in prolongation of their activated partial thromboplastin time (APTT) to 1.5 to 2.5 times baseline had more profound reduction in PMN counts following a challenge with the secretagogue phorbol myristate acetate (PMA). These studies demonstrate that heparin can interact synergistically with chemotactic stimuli known to evoke lactoferrin release, which in turn leads to enhancement of PMN aggregation. Our data further suggest that heparin may be contraindicated in the treatment of syndromes with increased PMN aggregation such as endotoxin-induced Schwartzman-type reactions.

Animals↗
PubMed1983

Plasma lactoferrin reflects granulocyte activation in vivo.

N-formyl-met-leu-phe (FMLP) causes polymorphonuclear leukocytes (PMN) to secrete and become "sticky" in vitro. We related these events to in vivo FMLP-induced neutropenia. FMLP was intravenously administered to anesthetized rabbits in doses ranging from 0.01 microgram to 1.0 microgram. Controls received phosphate-buffered saline (PBS), the diluent for FMLP. Blood pressure, respiratory rate, and arterial Po2 were monitored. High and intermediate doses of FMLP caused a dramatic but transient decrease in blood pressure and an increase in respiratory rate. Prior to FMLP infusion, plasma lactoferrin level was 6.4 +/- 4.1 micrograms/ml, and the absolute granulocyte account (AGC) was 2008 +/- 1229 (mean +/- SD). There was a positive linear correlation between AGC and plasma lactoferrin level prior to injection of FMLP (R2 = 0.74, p less than 0.01). At 1 min after FMLP injection, the percent change in AGC decreased as an exponential function of dose to as low as 10% of baseline (R2 = 0.86, p = 0.002) and plasma concentration of lactoferrin increased as an exponential function of dose to as high as 30 micrograms/ml (R2 = 0.84, p = 0.006). Thus, FMLP-induced neutropenia is associated with increased levels of plasma lactoferrin, suggesting that PMN are induced to degranulate in vivo.

Animals↗
PubMed1982

Human leukocyte interferon for the treatment of varicella in children with cancer.

Human leukocyte interferon was evaluated as a treatment for varicella in a randomized double-blind, placebo-controlled study carried out in two phases. A total of 44 children being treated for cancer were enrolled within 72 hours of the appearance of the exanthem. The mean number of days of new lesion formation was 3.8 +/- 1.89 (+/- S.D.) in the interferon recipients and 5.3 +/- 2.56 in the placebo recipients (P less than 0.05). Eighty-one per cent of the interferon recipients had had no new lesions for 24 hours by Day 7, as compared with 56 per cent of the placebo recipients (P less than 0.025). In the second, higher-dose phase of the study 92 per cent of the interferon recipients had had no new lesions for 24 hours by Day 6, as compared with 45 per cent of the placebo recipients (P less than 0.025). Three of 21 placebo recipients died of progressive varicella. Two of the 23 interferon recipients died two to three weeks after the onset of varicella; viral cultures were negative in one of these patients, and the second had recurrent viremia at the end of the treatment period. Among the survivors, treatment with interferon reduced the number of patients who had life-threatening dissemination (none of 21 vs. three of 18; P = 0.053). We conclude that interferon had an antiviral effect against varicella virus in immunocompromised patients.

Chickenpox↗
PubMed1982

Elevated sister chromatid exchange and cell cycle analysis in bone marrow in childhood ALL.

Sister chromatid exchange (SCE) frequencies were analyzed in both stimulated and unstimulated bone marrow samples from eight patients recently found to have childhood acute lymphocytic leukemia (ALL). Six of the patients had elevated SCE frequencies in stimulated marrow when compared to control values. In unstimulated marrow, all four patients had elevated SCE frequencies. These data agree with peripheral leukocyte findings in ALL. Cell cycle analysis revealed no significant differences between the patient marrows and the control marrows. Since no correlation between cell cycle distribution and SCE frequency was found, it is suggested that the differences in SCE observed may be related to the type of proliferating cell.

Bone Marrow↗
PubMed1982

Usefulness of bone marrow imaging in childhood malignancies.

Two hundred six technetium-99m sulfur colloid bone marrow scans in 110 pediatrics patients were reviewed. The normal distribution of sulfur colloid in the lower extremities in various age groups was established. There was progressive loss of uptake with increasing age from less than two years to greater than ten years. Tumor replacement was seen as regions of decreased radioactivity, and the extent of the scan defect paralleled the response of the disease to therapy. Both chemotherapy and irradiation resulted in an extension of the Tc-99m SC to peripheral marrow sites. In irradiated areas, marrow scan defects were demonstrated and generally recovered normal activity by six months after the completion of therapy. Marrow scan abnormalities caused by tumor replacement were present in four patients despite normal bone scans and radiographs. Ultimate confirmation of tumor involvement was by needle aspiration or biopsy. Persistent marrow defects were seen in two patients with neuroblastoma who had remission of their disease: biopsy revealed myelofibrosis. Technetium-99m sulfur colloid bone marrow scanning is a sensitive monitor of altered marrow activity associated with pediatric hematologic or oncologic diseases.

Bone Marrow↗
PubMed1982

The use of antithymocyte globulin in the treatment of severe aplastic anemia in children.

The benefit of antithymocyte globulin in severe aplastic anemia in the pediatric age group was assessed. Four children received ten alternate-day courses of ATG (horse antihuman thymocyte globulin) as well as antihistamines and corticosteroids to minimize allergic reactions. The outcome of 19 other children with severe aplastic anemia who received ATG was also summarized. Combined data reveal that 12 of 23 have had a complete or partial response with residual thrombocytopenia and a probability of 48% survival one year from the start of ATG therapy as projected by life table analysis. Only one death has been recorded in the responding group. Response rate did not appear to be influenced by age, sex, etiology, initial blood count, interval prior to ATG therapy, or dose of ATG employed. Complications were minimal and included minor urticarial reactions and intermittent fever. Therapy with ATG should be considered in childhood severe aplastic anemia when bone marrow transplantation is not possible.

Actuarial Analysis↗
PubMed1982

The influence of vitamin E on human polymorphonuclear cell metabolism and function.

These studies on the effect of administration of 1,600 units of vitamin E to humans indicated the following responses to the PMNs (TABLE 6). Functional alterations occur with an increased ability to ingest particles but a mild decrease in bactericidal potency of the PMN. Although the respiratory burst is slightly enhanced as is superoxide anion release, H2O2 release from the PMN is markedly impaired. The hexose monophosphate shunt activity, which is dependent on intracellular H2O2 is decreased during phagocytosis. Membrane responses such as changes in order parameter during phagocytosis as reported by the stearic acid analogue probe 5DS are similar to those of normal PMNs. The release of arachidonic acid from membranes of vitamin E PMNs during phagocytosis of opsonized zymosan is slightly enhanced, indicating normal phospholipase A2 activation. NADH oxidase-derived H2O2 is not impaired within phagocytic generated by NADPH oxidase in phagocytic vesicles, accounting for impairment in HMPS activity and bactericidal activity in these cells.

Arachidonic Acid↗
PubMed1982

Membrane-bound lactoferrin alters the surface properties of polymorphonuclear leukocytes.

Polymorphonuclear leukocytes (PMN) aggregate and avidly attach to endothelium in response to chemotactic agents. This response may be related in part to the release of the specific granule constituent lactoferrin (LF). We found by using immunohistology and biochemical and biophysical techniques that LF binds to the membrane and alters the surface properties of the PMN. Upon exposure of PMN treated with 5 micrograms/ml cytochalasin B to 2 x 10(-7) M formyl-methionine-leucine-phenylalanine for 5 min, the PMN mobilized LF to their surface as observed by immunoperoxidase staining for LF. At added LF levels ranging from 4 to 15 micrograms/10(7) PMN there was a dose-dependent reduction in PMN surface charge reaching 4 mV, when the partitioning into the membrane of a charged amphipathic nitroxide spin label was measured by electron spin resonance spectroscopy, whereas transferrin was without effect. When 125I-FeLF was added to human PMN in increasing amounts and the results corrected for the residual amount of free LF contaminating the cells, the PMN were saturated with LF at concentrations between 100 and 200 nM in the medium. Human PMN bound 1.35 x 10(6) molecules per cell and the calculated value for the association constant for these receptors was 5.2 x 10(6) M-1. Additionally, 6 micrograms/ml LF served as an opsonin for rabbit MN to promote PMN uptake by rabbit macrophages, when assessed by electron microscopy, but lysozyme did not. These studies indicate that LF can bind to the surface of the PMN and reduce its surface charge. This correlates with enhanced "stickiness" leading to a variety of cell-cell interactions.

Animals↗