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Biomedical subjects

B Christian

Publications and source records attributed to B Christian.

At least 19 recordsLinked to original sources
PubMed1998

The anti-MUC1 monoclonal antibody BCP8 can be used to isolate and identify putative major histocompatibility complex class I associated amino acid sequences.

MHC class I molecules were isolated from the MUC1-positive human breast adenocarcinoma cell line MCF-7 by immunoaffinity using the panreactive anti-class I monoclonal antibodies (MAb) W6/32. Acid-eluted peptides from the class I molecules were separated twice by high-performance liquid chromatography and tested for reactivity with the MAb BCP8, which reacts with the minimal MUC1 core peptide sequence PDTRPA. A peak with strong and specific BCP8 reactivity was found in fractions eluting at 16.5-17.5 min. The protocol used for the MUC1+ pancreatic adenocarcinoma cell line CAPAN-1 (HLA.A2) was to perform sequential affinity purifications of class I molecules using MAb W6/32, followed by affinity purification of HLA.A2 molecules by the HLA.A2.1-specific MAb, MA2.1, and high-performance liquid chromatography fractionation of the acid-eluted material. A single peak with MAb BCP8 reactivity was noted at 18-19 min. The protocol for the MUC1+ breast adenocarcinoma cell line SKBr-3 (HLA.A11,B40), which used A11- and B40-specific MAbs, also resulted in the detection of BCP8-specific peaks at approximately 18-19 min. A preliminary mass spectral analysis of BCP8 affinity-purified class I associated material surprisingly revealed the presence of two 3-mer MUC1 amino acid sequences and one 6-mer sequence. A synthetic 9-mer MUC1 peptide, TSAPDTRPA, containing the isolated fragments was found to cause strong class I up-regulation in T2 cells as well as to serve as an epitope for CTL generated in a primary in vitro immune response. These studies suggest that MUC1-derived peptides are processed and presented in the context of MHC class I molecules on the surface of tumor cells and support the use of MAb BCP8 to further define MHC class I associated MUC1 motifs.

Antibodies, Monoclonal↗
PubMed1998

A placebo-controlled study of recombinant human granulocyte-macrophage colony-stimulating factor administered during and after induction treatment for de novo acute myelogenous leukemia in elderly patients. Groupe Ouest Est Leucémies Aiguës Myéloblastiques (GOELAM).

The complete remission (CR) rate after intensive chemotherapy for acute myelogenous leukemia (AML) remains low in elderly patients, mainly because of a higher infectious mortality rate related to neutropenia and an increased incidence of adverse prognostic factors. Granulocyte-macrophage colony-stimulating factor (GM-CSF) has been shown to potentially recruit leukemic blasts into cell cycle and improve cytotoxic effects when given during chemotherapy, and to shorten the duration of neutropenia when administered after chemotherapy. Two hundred forty patients aged 55 to 75 years who had newly diagnosed AML were randomly assigned to receive placebo or Escherichia coli-derived GM-CSF (5 micrograms/kg/d by 6-hour intravenous infusion) starting during induction chemotherapy on day 1 and continued through and after chemotherapy until recovery of neutrophils, or evidence of regrowth of leukemia, or up to day 28. Induction chemotherapy consisted of idarubicin (8 mg/m2/d on days 1 to 5) and cytarabine (100 mg/m2/d on days 1 to 7). The study drug was not administered subsequent to the induction course. Patients who achieved a CR received continuous maintenance therapy for 1 year with four quarterly reinduction courses; in the 55- to 64-year age subgroup, patients were randomly assigned to receive or not a consolidation course before maintenance therapy. The CR rate was similar in the GM-CSF and placebo groups (63% and 60.5%, respectively; P = .79). The mortality, rate of resistant disease, and rate of regrowth of leukemia were also similar in both groups. The time to neutrophil recovery was shorter in patients who received GM-CSF (24 v 29 days; P = .0001), but the incidence and characteristics of infectious events were not different. The 2-year disease-free survival (DFS) rate was significantly improved in the GM-CSF group (48% v 21% in the placebo group; P = .003). This effect was highly significant in the cohort of patients aged 55 to 64, but only marginal in patients >/=65 years of age. There was a trend toward a longer overall survival (OS) in the GM-CSF group (P = .082). In summary, the administration of GM-CSF, concomitantly with chemotherapy and thereafter during induction course in AML, shortened the time to neutrophil recovery, but did not improve the CR rate in patients aged 55 to 75. Nonetheless, DFS and OS were significantly prolonged in patients aged 55 to 64 treated with GM-CSF. These results are promising and further evaluation of myeloid growth factors in AML is warranted.

Age Factors↗
PubMed1998

Palmitate oxidation by the mitochondria from volume-overloaded rat hearts.

In this work, an attempt was made to identify the reasons of impaired long-chain fatty acid utilization that was previously described in volume-overloaded rat hearts. The most significant data are the following: (1) The slowing down of long-chain fatty acid oxidation in severely hypertrophied hearts cannot be related to a feedback inhibition of carnitine palmitoyltransferase I from an excessive stimulation of glucose oxidation since, because of decreased tissue levels of L-carnitine, glucose oxidation also declines in volume-overloaded hearts. (2) While, in control hearts, the estimated intracellular concentrations of free carnitine are in the range of the respective Km of mitochondrial CPT I, a kinetic limitation of this enzyme could occur in hypertrophied hearts due to a 40% decrease in free carnitine. (3) The impaired palmitate oxidation persists upon the isolation of the mitochondria from these hearts even in presence of saturating concentrations of L-carnitine. In contrast, the rates of the conversion of both palmitoyl-CoA and palmitoylcarnitine into acetyl-CoA are unchanged. (4) The kinetic analyses of palmitoyl-CoA synthase and carnitine palmitoyltransferase I reactions do not reveal any differences between the two mitochondrial populations studied. On the other hand, the conversion of palmitate into palmitoylcarnitine proves to be substrate inhibited already at physiological concentrations of exogenous palmitate. The data presented in this work demonstrate that, during the development of severe cardiac hypertrophy, a fragilization of the mitochondrial outer membrane may occur. The functional integrity of this membrane seems to be further deteriorated by increasing concentrations of free fatty acids which gives rise to an impaired cooperation between palmitoyl-CoA synthase and carnitine palmitoyltransferase I. In intact myocardium, the utilization of the in situ generated palmitoyl-CoA can be further slowed down by decreased intracellular concentrations of free carnitine.

Adenosine Triphosphate↗
PubMed1998

Functional MRI statistical software packages: a comparative analysis.

Currently, there are many choices of software packages for the analysis of fMRI data, each offering many options. Since no one package can meet the needs of all fMRI laboratories, it is helpful to know what each package offers. Several software programs were evaluated for comparison of their documentation, ease of learning and use, referencing, data input steps required, types of statistical methods offered, and output choices. The functionality of each package was detailed and discussed. AFNI 2.01, SPM96, Stimulate 5.0, MEDIMAX 2.01, and FIT were tested. FIASCO, Yale, and MEDx 2.0 were described but not tested. A description of each package is provided.

Algorithms↗
PubMed1997

Metabolic alterations in muscle of thermally injured rabbits, measured by positron emission tomography.

The hypermetabolic inflammatory state that occurs after major trauma has been extensively studied at the whole body level, however, there is only limited information on metabolic changes in individual tissues. In this study, the effect of thermal injury on metabolic function of uninjured hind limb muscle of rabbits was measured noninvasively by positron emission tomography (PET). Rabbits were subjected to full thickness burn on 25% of their body surface area. Two to three weeks after injury, PET and arterial blood sampling was performed during inhalation of 15O2, C15O2 and 11CO and after injection of 18FDG. The tissue and blood data were analyzed by standard kinetic models for blood flow, oxygen extraction fraction (OEF), oxygen utilization and glucose metabolism. A total of seven injured and five sham animals were studied. Total body oxygen consumption was measured by indirect calorimetry and plasma concentrations of glucose, insulin and IGF-1 were measured with standard assays. Compared to sham rabbits, blood flow to muscle of injured animals was unchanged. However, OEF, oxygen utilization and glucose metabolism were significantly reduced (p<0.01) in uninjured muscle of burned rabbits. These data demonstrate that thermal injury is associated with alterations in muscle metabolism, which are not related to change in blood flow.

Animals↗
PubMed1996

Separation of enantiomers of drugs by capillary electrophoresis. III. Beta-cyclodextrin as chiral solvating agent.

Enantiomer separation by capillary zone electrophoresis was studied for a set of 34 chiral drugs. Keeping the concentration of beta-cyclodextrin as a chiral solvating agent as constant as possible led to the separation of seven enantiomeric pairs. Carvedilol, Tetryzoline, Tropicamide and Zopiclone gave a baseline separation, Chlorphenamine, Ketamine, and Orciprenaline a partial separation. Statistical analysis revealed that the best separation factors were observed for a medium degree of interaction with the cyclodextrin. A theory explaining this effect provides a helpful guideline for further optimization.

Azabicyclo Compounds↗
PubMed1995

Sequential induction chemotherapy with vincristine, daunorubicin, cyclophosphamide, and prednisone in adult acute lymphoblastic leukemia.

Sequential chemotherapy with vincristine, daunorubicin, cyclophosphamide, and prednisone doses was administered to 57 adult patients with acute lymphoblastic leukemia (ALL). Complete remission (CR) was achieved in 51 (89%, 95% confidence intervals, [CI] 78-96%). Among patients achieving CR, 62% were in CR after one sequence of chemotherapy, 23% after two sequences, and 5% after three sequences. Six patients (11%) had resistant disease. All patients experienced profound myelosuppression. Median time to recovery of neutrophils > 0.5 x 10(9)/1 was 22 days (range: 5-89 days), and of platelets > 100 x 10(9)/1 21 days (range: 0-45 days). Nonhematologic WHO grade 3 or more side effects consisted predominantly of hyperbilirubinemia (7%), mucositis (5%), nausea and vomiting (2%), and cutaneous toxicity (1%). Severe infectious complications occurred in only 14% of cases. One patient (2%, 95% CI 0-9%) died of therapy-related toxicity while in early CR. We concluded that sequential use of prednisone seemed at least as effective as continuous administration at the expense of a few adverse side effects.

Adolescent↗
PubMed1993

Self-efficacy, coping, and well-being among nursing students sexually abused in childhood.

Preparing nursing students to work with sexually abused children has received little attention by pediatric nurse educators. These students often are themselves survivors of such abuse. The population of undergraduate nursing students attending a major university was invited to participate in a mailed survey to test hypotheses concerning differences in self-efficacy, coping, and well-being between subjects who were sexually abused in childhood and those who were not. A total of 87 students (79 women and 8 men) responded by returning the completed survey. Forty-seven percent of the women (n = 37) and 38% of the men (n = 3) in the sample reported having had one or more unwanted sexual experiences in childhood. Significant correlations were found between self-efficacy and confrontive coping (r = .58), emotive coping (r = .49), and palliative coping (r = -.46); between well-being and emotive coping (r = -.24); and between well-being and palliative coping (r = -.25). One-way analysis of variance (ANOVA) techniques were used to analyze differences in self-efficacy, coping (confrontive, emotive, and palliative), and well-being between the two groups (abused = 40 and not abused = 47). A significant difference in emotive coping was found. These findings suggest that nurse educators and administrators need to be sensitive to pediatric nurses' childhood sexual experiences. Such nurses must be knowledgeable and emotionally equipped to support the child and family through the process of recovery. It is important for them to be aware of how their own coping strategies and well-being affect the care they provide vulnerable children.

Adaptation, Psychological↗
PubMed1979

Isolation and partial characterization of the multiple forms of deoxyribonucleic acid-dependent ribonucleic acid polymerase in the fungus Podospora anserina.

Three DNA-dependent RNA polymerases have been isolated and partially purified from the mycelium of the fungus Podospora anserina. Separated by DEAE-Sephadex chromatography, they have been designated RNA polymerases I, II, and III according to their order of elution. Their catalytic properties and alpha-amanitin sensitivity are in agreement with those of the homologous enzymes found in other eukaryotic organisms. The three enzymes exhibit rather sharp monophasic ammonium sulfate dependence with optima which are, respectively, 0.035 M, 0.050 M, and 0.075 M. Enzyme I has the largest Mn2+/Mg2+ activity ratio, shows a marked preference for native DNA, and is insensitive to alpha-amanitin. Enzyme III uses poly(dA-dT) in preference to native DNA as template and is only partially sensitive to alpha-amanitin. Enzyme II is sensitive to alpha-amanitin, but high concentrations of the toxin are required for inhibition compared to other eukaryotic class II enzymes. Three similar RNA polymerases with comparable levels of activity were found in the temperature-dependent VR strain when cellular incompatibility, leading to a rapid cessation of RNA synthesis, was induced.

Amanitins↗
PubMed1977

Immunofluorescent technique for the detection of antibodies to n-DNA: comparison with radioimmunoassay.

One hundred and six sera from patients with systemic lupus erythematosus (SLE), 20 from patients without SLE but with a positive FANA, and 50 controls were tested for the presence of antibodies to n-DNA, using an immunofluorescent technique with the kinetoplast of Crithidia luciliae as a substrate. A high degree of correlation existed between the results obtained with this technique and a Millipore radioimmunoassay method using a well characterized tritiated native human DNA. The result with the immunofluorescent method could be expressed semiquantitatively as a titer, if serial serum dilutions were used. Results in patients with SLE correlated well with disease activity. We conclude that the immunofluorescent technique can provide a useful alternative to a radioimmunoassay for the detection of antibodies to n-DNA. In addition, as this substrate is known to contain pure n-DNA, problems do not arise with contamination with singlestranded DNA as sometimes occurs with other test antigens. This avoids the detection of antibodies reacting only with single-stranded areas and consequently increased the specificity of the reaction.

Antibodies, Antinuclear↗
PubMed1969

Sodium ions and the secretion of catecholamines.

1. Perfusion of bovine adrenal glands with a potassium-free Tyrode solution results in an increased spontaneous release of catecholamines and an increased response to stimulation with carbamylcholine.2. Perfusion with a Tyrode solution containing 70 mM-KCl causes a marked secretion of catecholamines and a subsequent inhibition of secretion in response to stimulation with carbamylcholine.3. Perfusion with sodium-free media abolishes or severely reduces the secretory response of the gland to carbamylcholine and to 70 mM-KCl although the basal secretion shows an initial rise.4. Perfusion with sodium-deficient media permits some retention of the secretory response.5. A possible role for intracellular sodium ions in the secretion of catecholamines is discussed.

Adrenal Glands↗