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Biomedical subjects

R L Baehner

Publications and source records attributed to R L Baehner.

At least 91 records · Page 5Linked to original sources
PubMed1981

Nuclear medicine studies in evaluation of skeletal lesions in children with histiocytosis X.

Radiographs were compared with 99mTc scans of the bones and bone marrow as well as 67Ga-citrate scans to evaluate their sensitivity in identifying skeletal lesions in 21 children with histiocytosis X. Seven of 20 bone scans were completely normal in patients with extensive radiographic evidence of skeletal disease. In only one patient were bone scan changes demonstrated prior to radiographic abnormalities. None of the lesions was "cold" on the bone scans. 99mTc-sulfur colloid bone marrow scans and 67Ga-citrate whole-body scans were not valuable. Radiographic survey of the skeleton should be the primary diagnostic test employed in patients with histiocytosis X who have suspected skeletal lesions. Bone scans should be obtained only when the radiographs are normal or equivocal.

Bone Diseases↗
PubMed1981

Accumulation of circulating macrophages in lungs of guinea pigs exposed to hyperoxia.

Superoxide dismutase (SOD) and glutathione peroxidase (GPx) key enzymes in alveolar macrophages regulating levels of superoxide anion and hydrogen peroxide, respectively, were observed to fluctuate in response to FIO2 of 50 and 85% for 18 to 90 hr. At the lower oxygen tension, SOD rose two-fold and GPx decreased significantly by 18 hr and throughout the exposure periods compared to a delayed increase in SOD activity which was not sustained beyond 66 hr of exposure and a sustained rise in GPx to an FIO2 of 85%. Peritoneal macrophages containing lower SOD activity and greater GPx activity than resident alveolar macrophages upon injection into the circulation resulted in 10-fold accumulation in the lungs during exposure of animals to FIO2 of 85% but not at 50%. This study indicates that brief exposure to FIO2 of 85% but not 50% resulted in alterations of the vascular integrity of the lungs resulting in the accumulation of circulating macrophages to the alveolar macrophage pool. The delayed rise in SOD activity and the sustained increase in GPx activity in alveolar macrophages from animals exposed to FIO2 of 85% could in part be related to this influx of circulating macrophages with enzymatic characteristics observed for peritoneal macrophages.

Animals↗
PubMed1981

Functions of human monocyte and lymphocyte subsets obtained by countercurrent centrifugal elutriation: differing functional capacities of human monocyte subsets.

Two monocyte subsets from the peripheral blood of healthy humans were isolated by countercurrent centrifugal elutriation (CCE), and their functional heterogeneity was assessed. Cell volume of the smaller monocyte population was (332 +/- 32 mu 3), compared with the larger monocytes (380 +/- 30 mu 3). Superoxide release by large monocytes exposed to opsonized zymosan was 1.5-fold more active than those of small monocytes. Furthermore, the production of colony-stimulating factor (CSF) and myeloperoxidase activity by the larger monocytes was 2-fold and 1.4-fold greater than that of small monocytes, respectively. Thus, CCE provides a useful means to isolate 2 subsets of monocytes with similar functional properties but quantitatively different activities. This suggests that the 2 subsets may be closely related in their developmental spectrum.

Bone Marrow Cells↗
PubMed1981

Amphotericin-B promotes leukocyte aggregation of nylon-wool-fiber-treated polymorphonuclear leukocytes.

Severe pulmonary reactions have been reported in patients receiving leukocyte transfusion and amphotericin-B. To study the interaction of amphotericin-B with polymorphonuclear leukocytes (PMN), purified human PMN were incubated with 200 mg of nylon wool fiber for 60 min either in the absence or presence of 2 mM EDTA. PMN were recovered in acid citrate dextrose solution and were suspended in balanced salt solution for determination of their aggregation properties. The cells exposed to nylon wool fibers without EDTA aggregated in response to concentration as low as 1.25 micrograms/ml of amphotericin-B. Cells initially treated with EDTA, however, failed to aggregate. Serum from a patient treated with amphotericin-B aggregated PMN exposed to nylon wool fiber but not control cells, whereas serum taken before amphotericin was given without effect on the PMN treated with nylon wool fiber. Amphotericin-B at 5 micrograms/ml failed to potentiate the release of beta-glucocuronidase or lactic dehydrogenase by PMN treated by nylon wool beyond that seen with exposure to the fibers alone. Rabbit peripheral blood was similarly incubated with nylon wool fibers and the recovered PMN were infused into recipient rabbits that had received 1 mg/kg of amphotericin-B intravenously 1 hr prior to the infusion of the leukocytes. Rabbits were sacrificed 30 min after transfusion of PMN, and their lungs were excised for histologic sectioning. Those rabbits receiving a combination of amphotericin-B and 4 x 10(7) nylon-wool-fiber-treated PMN had evidence of pulmonary hemorrhage and accumulation of leukocytes in the pulmonary vasculature whereas those animals who received such cells alone had normal appearing lung tissue. In summary, amphotericin-B at concentrations achievable in vivo enhanced the aggregation of PMN damaged by incubation with nylon fiber with subsequent accumulation of the phagocytes in pulmonary tissue.

Amphotericin B↗
PubMed1981

Normal glucocorticoid receptor numbers in a child with glucocorticoid-resistant relapsed acute lymphocytic leukemia.

Glucocorticoid receptors were quantified in circulating lymphoblasts from a child with relapsed acute lymphocytic leukemia refractory to multiple glucocorticoid containing drug regimens. The number of receptor sites in this patient's lymphoblasts was found to be similar to the number of receptor sites in lymphoblasts from a group of newly diagnosed children with acute lymphocytic leukemia. This patient differs from previous reported cases of relapsed acute lymphocytic leukemia in that all previous relapsed patients with normal receptor numbers obtained complete remissions when glucocorticoid containing treatment regimens were employed.

Antineoplastic Agents↗
PubMed1981

Aplastic anemia complicating infectious mononucleosis: a case report and review of the literature.

A 12 1/2-year-old white girl developed pancytopenia and severe aplastic anemia three weeks following symptoms of infectious mononucleosis. Pancytopenia complicating infectious mononucleosis has been reported in only nine previous cases and only three were proven to have aplastic anemia. The mean time from onset of symptoms of infectious mononucleosis to the nadir of pancytopenia was 21.3 days with a range of seven to 49 days. Two patients died from complications of the pancytopenia. In those patients who recovered, the mean time from diagnosis of the pancytopenia to recovery of bone marrow function was 6.25 days with a range of four to eight days. In contrast to other causes of aplastic anemia, return of normal platelet levels coincided with recovery from pancytopenia. The etiology of the pancytopenia and aplastic anemia are unknown but immunologic causes are suspected because of the rapid recovery of the bone marrow and its possible responsiveness to steroids.

Adolescent↗
PubMed1981

Lactoferrin: a promoter of polymorphonuclear leukocyte adhesiveness.

Polymorphonuclear leukocytes (PMN) degranulate, adhere to vascular endothelium, or aggregate to each other following exposure of the cells to high concentrations of chemotactic stimuli such as formyl-methionyl-leucyl phenylalanine (FMLP). PMN released the specific granule product lactoferrin more readily in response to chemotactic stimuli, which correlated with promotion of PMN aggregation as measured by light transmission and enhanced PMN adherence. Both concanavalin A (Con-A) and phorbol myristate acetate (PMA), agents that lead to specific granule discharge, induced and sustained human PMN aggregation. Similarly, supernatants, generated from Con-A-treated PMN, aggregated fresh PMN in the presence of alpha-methylmannoside, a competitive inhibitor of the lectin. Anti-human lactoferrin IgG but not normal goat IgG blunted the aggregation elicited by both PMA and FMLP. Both human milk lactoferrin and rabbit PMN lactoferrin aggregated human lactoferrin promoted PMN adherence to endothelial cells. The enhanced PMN stickiness was correlated with the early phase of degranulation. Thus, PMN lactoferrin serves an autoregulatory role to retain PMN at inflammatory sites to amplify the inflammatory response.

Animals↗
PubMed1981

Membrane fluidity changes accompanying phagocytosis in normal and in chronic granulomatous disease polymorphonuclear leukocytes.

We have studied membrane fluidity changes in polymorphonuclear leukocytes (PMN) during phagocytosis. Membrane fluidity was assessed by electron spin resonance (ESR) using a nitroxide-substituted stearic acid analog (5DS) as a spin probe. PMN from normal subjects and from 3 CGD patients (2 males, 1 female) were incubated in Kreb's Ringers phosphate with or without opsonized zymosan. ESR spectra were obtained and the order parameter (S), which is inversely related to membrane fluidity, was calculated. Without zymosan addition, S for normal (0.638) and for CGD (0.635) were not significantly different (p less than 0.35). The S values indicate that under resting conditions the molecular environment of the CGD membrane is similar to that of normal PMN membranes. However, with addition of opsonized zymosan, the normal, but not the CGD, PMN showed a significant increase (CGD, S = 0.638; normal, S = 0.647; p less than 0.001). This change in S for the normals is consistent with a more restricted movement of 5DS. Treatment of normal PMN with a mixture of scavengers specific for H2O2 (catalase, 1600 U/ml), O2-.(superoxide dismutase, 100 micrograms/ml), and for HO., (sodium benzoate, 1mM) during zymosan stimulation gave S values similar to those of resting cells. Catalase alone also lowered S value, suggesting that H2O2 was instrumental in causing the initial S value increase. This idea was supported by studies in which CGD cells were incubated with zymosan in the presence of glucose oxidase, an enzyme that catalyzes glucose oxidation resulting in the direct reduction of molecular oxygen to H2O2. Our results indicate that reduced O2 by-products, particularly H2O2, can cause altered biophysical properties of PMN membrane during phagocytosis.

Granulomatous Disease, Chronic↗
PubMed1980

Methotrexate/L-asparaginase combination chemotherapy for patients with acute leukemia in relapse: a study of 36 children.

Cyclic administration of methotrexate (MTX) and L-Asparaginase (L-Asp) was utilized either as induction and maintenance chemotherapy or as maintenance chemotherapy alone following induction with other medications in treating 36 children with multiple relapses of acute leukemia. A complete remission rate (CR) of 67% was obtained in children with null-cell acute lymphocytic leukemia (ALL). The average length of remission was greater than four months. One of three patients with T-cell ALL and one of two patients with B-cell ALL achieved CR. In six cases of acute nonlymphocytic leukemia (ANLL), two patients achieved CR. One of two patients with terminal deoxynucleotidyl transferase (TdT) negative myeloblastic transformation of Ph'-positive chronic myelogenous leukemia (CML) obtained a CR lasting 20 weeks. Toxicity secondary to the chemotherapy included bone marrow suppression, hepatic injury, nausea, diarrhea, stomatitis, and allergic reactions to L-Asp. One case of subacute necrotizing leukoencephalopathy was seen.

Acute Disease↗
PubMed1980

Prevention of pneumocystis pneumonia. Use of continuous sulfamethoxazole-trimethroprim therapy.

Owing to a 15% attack rate of Pneumocystis carinii pneumonitis (PCP) among the leukemic population of Riley Hospital, Indianapolis, a two-year study using continuous low-dosage sulfamethoxazole-trimethoprim to prevent PCP was started in January 1977. A total of 229 pediatric cancer patients considered at high risk for getting PCP received prophylaxis, while 19 additonal low-risk cancer patients did not receive sulfamethoxazole-trimethoprim. None of these 248 patients contracted PCP. However, five cases of PCP did occur among ten additional high-risk patients who failed to receive this preparation for a variety of reasons. Complications of the continuous prophylaxis program included neutropenia, rash, and gastrointestinal complaints. This study confirms that continuous, low-dosage sulfamethoxazole-trimethoprim prophylaxis is effective in preventing PCP in susceptible immunosuppressed patients but is ineffective in eradicating the organism from the population at risk.

Administration, Oral↗
PubMed1980

Intracranial hemorrhage and focal seizures secondary to use of L-asparaginase during induction therapy of acute lymphocytic leukemia.

L-Asparaginase is commonly used for induction therapy of acute lymphocytic leukemia of childhood. Severe clinical bleeding secondary to clotting dysfunction has not been previously reported. We observed intracranial hemorrhagic infarcts with focal seizures and hemiparesis associated with clotting abnormalities, including severe hypofibrinogenemia, probably the result of L-asparaginase administered during induction therapy of acute lymphocytic leukemia.

Afibrinogenemia↗