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Biomedical subjects

J E Russo

Publications and source records attributed to J E Russo.

9 recordsLinked to original sources
PubMed1990

Direct demonstration of elevated aldehyde dehydrogenase in human hematopoietic progenitor cells.

Relative levels of cytoplasmic aldehyde dehydrogenase (ALDH) were determined in selected subpopulations of normal human bone marrow cells using a flow cytometric assay that simultaneously detects a cell surface antigen (as a marker of cell lineage and developmental stage) and the level of ALDH. The intracellular level of this enzyme has been shown to be directly related to cellular resistance to activated cyclophosphamide and is believed to be important in the survival of cells capable of repopulating marrow in autologous bone marrow transplant procedures. Western blot analysis and flow cytometric analysis of four murine cell lines with known ALDH levels were used to establish the relation between ALDH content and fluorescence with an affinity-purified anti-mouse ALDH antibody. An affinity purified anti-human ALDH antibody, characterized by immunoblotting of cytosolic extracts of cell lines with known ALDH content, was used to determine relative ALDH levels in the marrow subpopulations. We found that hematopoietic progenitor cells express the highest level of ALDH, while lymphocytes express the lowest level. Immature erythroid cells express ALDH at a level intermediate between progenitor cells and lymphocytes.

Aldehyde Dehydrogenase↗
PubMed1989

The validity of verbal protocols.

The reactivity of a "think aloud" verbal protocol and the veridicality of different retrospective protocols were tested over four dissimilar tasks. Generating a concurrent protocol altered accuracy in two tasks, simple addition and a choice between two gambles, and generally prolonged response times. Such reactivity partially qualifies the dominant theory of protocol generation (Ericsson & Simon, 1984). Retrospective protocols yielded substantial forgetting or fabrication in all tasks, supporting the consensus on the nonveridicality of these methods. It is concluded that protocol validity should be based on an empirical check rather than on theory-based assurances.

Adult↗
PubMed1988

Characterization of cytosolic aldehyde dehydrogenase from cyclophosphamide resistant L1210 cells.

The cytosolic aldehyde dehydrogenase (ALDH) isozyme from cyclophosphamide (CPA) resistant L1210 cells (L1210/CPA) was purified to apparent homogeneity using ternary enzyme complex-dye ligand chromatography. The purified isozyme migrates as a single band at Mr 51,000 in sodium dodecyl sulfate polyacrylamide gel electrophoresis and as a single charge species at isoelectric point = 5.8 in isoelectric focusing. Micromolar Km values were estimated with both propionaldehyde (Km = 5 microM) and 4-hydroxy cyclophosphamide (4-OH CPA) (Km = 4 microM) as substrates, indicating that this isozyme is capable of oxidizing the activated cyclophosphamide intermediate 4-hydroxy CPA/aldophosphamide to carboxyphosphamide. This isozyme is also potently inhibited by disulfiram (Ki = 6 microM) and 4-(diethylamino)benzaldehyde (Ki = 0.04 microM). Both of these inhibitors are capable of sensitizing L1210/CPA cells to activated CPA in clonogenic survival assays. Thus, the increased levels of only the cytosolic ALDH isoform in L1210/CPA cells appear to be the single phenotypic difference necessary for conferring resistance to CPA. Monospecific antibodies to the L1210/CPA isozyme have been used in Western blot analysis to detect nanogram levels of ALDH in cell and tissue extracts. These antibodies cross-react with the cytosolic isozyme in P388/CPA cells, mouse liver, mouse small intestine, and the 1C1C7 hepatoma cell line, whereas no ALDH is detected in sensitive L1210 or P388 cells. Also, these antibodies show little cross-reactivity with the mitochondrial isozyme from mouse liver or 1C1C7 cells. From immunological and inhibitor characterization, the soluble ALDH isozyme in L1210/CPA cells appears identical to the normal mouse tissue isozyme.

Aldehyde Dehydrogenase↗
PubMed1988

Enzymatic mechanisms of resistance to alkylating agents in tumor cells and normal tissues.

The presence in tumor cells and in normal cells of enzymes which metabolize and inactive alkylating agents appears to play a major role in determining the effectiveness of alkylating agents against human tumors and the toxicities of these agents to normal tissues. The enzyme aldehyde dehydrogenase appears to protect bone marrow and the gastrointestinal tract against toxicity from cyclophosphamide and other closely related oxazophosphorine agents. The presence of this enzyme in bone marrow stem cells facilitates the elimination of tumor cells from bone marrow suspensions, with preservation of the ability of the marrow suspension to reconstitute normal hematopoiesis in a patient. A variety of mouse and human tumors has been shown to be resistant to cyclophosphamide on the basis of an elevated aldehyde dehydrogenase content. The clinical significance of this type of resistance is currently being explored. Increased levels of glutathione-S-transferase have been shown to be associated with cellular resistance to a variety of alkylating agents. We have identified and characterized the conjugates of nitrogen mustards with glutathione. The formation of these conjugates is catalyzed by glutathione-S-transferase. The further study and characterization of these specific reactions should contribute to the understanding and quantitation of this type of alkylating agent resistance.

Aldehyde Dehydrogenase↗
PubMed1983

Strategies for multiattribute binary choice.

Based on eye-fixation patterns, strategies for multiattribute binary choice were classified as holistic (within an alternative) or dimensional (within an attribute across alternatives). In a task environment hospitable to both strategies, dimensional processing predominated. Even for alternatives like simple gambles, which require holistic computations, dimensional strategies were used as often as holistic ones. The dimensional strategies were augmented by two procedures that simplify the computations. These simplification procedures reduce cognitive effort at the cost of a relatively small increase in errors. However, for about half the subjects the use of these simplification procedures led to systematic violations of expected utility theory on certain choices. Both the preference for dimensional over holistic strategies and the adoption of simplifying procedures are compatible with the desire to reduce cognitive effort. We propose that strategies are selected to minimize the joint cost of errors and effort.

Choice Behavior↗
PubMedDate not supplied

Psychiatric illness in patients with chronic fatigue and those with rheumatoid arthritis.

OBJECTIVES: To identify psychiatric differences between patients with chronic fatigue and those with rheumatoid arthritis and to investigate whether patients meeting Centers for Disease Control (CDC) criteria for chronic fatigue syndrome (CFS) can be differentiated from patients with chronic fatigue on measures of disability and psychosocial distress. DESIGN: Cross-sectional study comparing 98 patients with chronic fatigue with 31 patients with rheumatoid arthritis on structured psychiatric interviews and patient questionnaires. Nineteen patients meeting CDC criteria for CFS were compared with 79 patients with chronic fatigue not meeting CDC criteria on questionnaires measuring disability and psychosocial distress. SETTING: Consecutive patients with chronic fatigue were selected from a chronic fatigue clinic at the University of Washington, and 31 consecutive patients with rheumatoid arthritis were sampled from a private rheumatology practice. MAIN RESULTS: Patients with chronic fatigue had a significantly higher prevalence of lifetime major depression and somatization disorder than did patients with rheumatoid arthritis. Patients with chronic fatigue also had a significantly higher prevalence of current and lifetime psychiatric diagnoses. Only 19 of 98 patients with chronic fatigue met CDC criteria for CFS. Patients meeting CDC criteria for CFS could not be differentiated from the larger group of patients with chronic fatigue on any study variable. CONCLUSIONS: Patients with chronic fatigue have a significantly higher burden of psychiatric illness than do patients with rheumatoid arthritis. The psychiatric illness preceded the development of chronic fatigue in over half the patients. Centers for Disease Control criteria for CFS did not select a subset of chronic fatigue patients who could be differentiated on disability or psychosocial parameters from patients with chronic fatigue who did not meet CDC criteria.

Adult↗