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Biomedical subjects

A Powell

Publications and source records attributed to A Powell.

71 records · Page 4Linked to original sources
PubMed1981

An overview of a multifactor-system theory of personality and individual differences: III. Life span development and the heredity-environment issue.

In Part III of this three-part series on multifactor-system theory, multivariate, life-span development is approached from the standpoint of a quantitative and qualitative analysis of the ontogenesis of factors in each of the six systems. The pattern of quantitative development (described via the Gompertz equation and three developmental parameters) involves growth, stability, and decline, and qualitative development involves changes in the organization of factors (e.g., factor differentiation and convergence). Hereditary and environmental sources of variation are analyzed via the factor gene model and the concept of heredity-dominant factors, and the factor-learning model and environment-dominant factors. It is hypothesized that the sensory and motor systems are heredity dominant, that the style and value systems are environment dominant, and that the cognitive and affective systems are partially heredity dominant.

Genotype↗
PubMed1980

Recombination between higher plant DNA and the Ti plasmid of Agrobacterium tumefaciens.

The Ti plasmid sequences (T-DNA) from the octopine-producing crown gall tumor A6S/2 were isolated by molecular cloning, using the bacteriophage lambda vector Charon 4A. Analysis of the cloned DNA segments indicates that the Ti plasmid sequences are covalently joined to plant nuclear DNA. These data demonstrate that genetic recombination between a eukaryote and a prokaryote can occur as a natural phenomenon.

Journal Article↗
PubMed1979

Immunological basis of close-contact sensitization to osteosarcoma.

Normal persons with a history of close contact with cancer patients often given positive responses in tests for specific tumor immunity. The present study was designed to establish the immunological relevance of such reactivity. Leukocyte adherence inhibition analysis was used to test responses of osteosarcoma (OS)-positive donors to extracts of OS. The test system proved highly specific in that positive leukocyte adherence inhibition responses were detected in 35 of 39 OS patients while only 6 to 7% of the controls were positive. Thus, the test system appears useful in the detection of OS. Two persons reactive presumably because of exposure to OS tissue gave booster-like leukocyte adherence inhibition responses on each reexposure. Reactivity was abrogated by treatment of their leukocytes with a goat anti-T-cell immunoglobulin G. Thus, the reactivity of cells from normal donors exposed to OS probably has an immunological basis, since the test system was highly specific, reflected anamnestic reactivity, and depended on lymphocytes (probably thymus dependent). These findings suggest that an OS-associated antigen can be transmitted horizontally, but the relation of immunity to risk remains obscure.

Antigens, Neoplasm↗
PubMed1979

Antigenic specificity and cellular mechanisms in leukocyte adherence inhibition analysis of immunity to simple proteins and hapten-protein conjugates.

The hemacytometer leukocyte adherence inhibition (LAI) assay was investigated with respect to immunological relevance, specificity, and cellular mechanisms. Humans were immunized to keyhole limpet hemocyanin, and rats were immunized to dinitrophenyl-bovine gamma-globulin. LAI analysis disclosed classic patterns of immune response kinetics. The LAI response was dose dependent in vitro with no inhibition at relatively high antigen doses. In vitro specificity in rats was restricted to the immunizing conjugate. Cells forming spontaneous E-rosettes were required for LAI reactions. Lymphokine production required the presence of E-rosette-forming cells. E-rosette-forming cells from normal donors lost adherence in the presence of lymphokine. The requirement for T-lymphocytes was confirmed in a human osteosarcoma system using independent criteria. Thus, the hemacytometer LAI depends upon T-lymphocyte collaboration via a lymphokine. It should be distinguished from the tube and microplate variants of LAI analysis because these appear to depend upon different mechanisms.

Animals↗
PubMed1978

A multi-systems theory of the structure and dynamics of motor functions.

A theoretical analysis of the structure and dynamics of human motor functioning is presented from the perspective of a general theory of individuality. Within multifactor-systems theory, the structural units of the six systems of integrative personality (i.e., sensory, motor, cognitive, affect, style, and value) are hierarchical factor structures. Integrative functioning, both within and among systems, is described via the principles of general systems and information-processing theory. Our theoretical synthesis of the structure and dynamics of human motor functioning involves conceptualizing the hierarchy of motor factors as: (a) the basic dimensions of individual differences in the motor domain, (b) classes of decomposable motor programs that specify the spatio-temporal organization of behavior, and (c) decomposable classes of processing components entailed by motor programs. Some of the implications for understanding the role of affect in motor functioning and some research suggestions were presented.

Journal Article↗
PubMed1974

The alcohol dehydrogenases of Drosophila melanogaster: frequency changes associated with heat and cold shock.

Laboratory populations of Drosophila melanogaster were subjected to heat and cold shock of sufficient duration and intensity to cause about 90 percent mortality. Alcohol dehydrogenase phenotypes were determined in survivors and controls. Significant changes in phenotypic frequencies occurred as a result of both treatments such that relative fitness appeared to be dependent on temperature. The alcohol dehydrogenase phenotype most frequently surviving heat under laboratory conditions is the same phenotype as that previously found to be higher in frequency in natural populations in areas with higher average temperature.

Alcohol Oxidoreductases↗
PubMedDate not supplied

Autogenous vein graft to restore ureteric continuity in dogs.

Free, autogenous vein segments were grafted to restore continuity of partially excised ureters in 12 mongrel dogs. Shortening and stricture formation of the vein graft occurred over the following four weeks. There was external adhesion around the graft but no urinary leakage, pooling or fistula. Intubation of the graft maintained patency but shortening occurred. Once the tube was removed, stricture formation and complete obliteration of the lumen of the graft occurred over the following few weeks. Prolonged splinting by biologically inert material may facilitate luminal patency and urothelial lining of the fibrous remnant of the venous graft. Gradual shortening of the graft eventually allows end-to-end anastomosis, without tension, as a second stage procedure.

Animals↗
PubMedDate not supplied

Renal hemangioendothelioma.

Renal hemangioendothelioma (HE) is an extremely rare malignant tumor. The sixth case is presented and all six analysed. The tumor affects middle-aged persons of either sex with past history of chronic renal disease and very recent onset of renal pain and hematuria. Anemia is common and a renal mass or tenderness is present. Pyelography shows poor function hydronephrosis, filling defect or collecting system distortion. A radical nephrectomy and radiotherapy is indicated and histology establishes the diagnosis. Renal HE appears to take a hurricane course and local recurrence and widespread vascular metastases occur in a matter of days or weeks after traditional cancer therapy. Industrial carcinogenesis is likely while chronic renal disease may predispose.

Female↗