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Biomedical subjects

P M Spielman

Publications and source records attributed to P M Spielman.

6 recordsLinked to original sources

The appeal cycle in early mother-child interaction: nature and implications of a finding from developmental research.

The appeal cycle was observed and delineated through research on mother-child interaction during the second year of life. As a repeated, circumscribed unit of developmental interaction, it is conceived to be an agent of developmental process and psychic structure formation. The appeal cycle has four phases: the adaptational phase, the distress phase, the appeal phase, and the interactional phase. The progression from the adaptational into the distress and appeal phases evidences the child's separation anxiety and failure of self-regulation in response to the experimentally induced attenuation of the mother-child relationship. A successful interactional phase reestablishes the relationship, regulates and restores the child's emotional equilibrium, and enables a return to self-regulation and adaptation. Because the interaction reinforces the functions and structures being developed through identification with the mother, the interactional phase is conceived to be an instrumental event in the mediation of psychic structure formation. The appeal cycle is discussed in comparison with similar phenomena in earlier phases of development and with other studies addressing development during the first two years of life. Directions for future research are noted.

Adaptation, Psychological↗

An exploratory study of mother-child interaction during the second year of life.

The aim of this study was to further understanding of development during the crucial second year of life. The study employed a naturalistic, semistructured situation for the observation of mother-child behavior. The experimental stimulus was the progressive diversion of the mother's attention away from her child. This diversion evoked separation anxiety in the child and the individual and interactive regulatory behaviors of the mother-child pair. Concurrently, the child's behavior was observed in a play group situation. One set of rating scales was devised for assessment of the mother-child interaction, and another set for assessment of the child's functioning in the play group. The major hypothesis was that maternal and child behaviors that foster the child's successful handling of phase-specific stresses and developmental tasks will be positively correlated with the child's functioning in the play group. This hypothesis is supported by the findings of the study.

Dependency, Psychological↗

Acridine binding by Escherichia coli: pH dependency and strain differences.

Acridine dye binding by cells of Escherichia coli has been characterized in terms of a number of parameters. There is a temperature-dependent, readily reversible binding of acriflavine which occurs to a greater extent with acridine-sensitive mutants of E. coli K-12 than with wild-type E. coli B or K-12. There is an essentially irreversible internal binding of acriflavine which occurs when the cellular permeability barriers are destroyed or altered by heat-treatment, elevated pH, treatment with toluene or phenethyl alcohol, or infection with bacteriophage T2 or T4. Both the reversible and the irreversible binding of acridines occurs more effectively with the acridine dye acriflavine than with the related dye proflavine, and still less effectively with 9-aminoacridine and quinacrine. These properties of acridine binding can be correlated with various inhibitory effects of the dyes on the cells.

Acridines↗

Cation fluxes and permeability changes accompanying bacteriophage infection of Escherichia coli.

Infection of Escherichia coli by bacteriophage T2 was accompanied by a rapid but transient increase in the rate of loss of small molecules from the bacterial cells. This transient leakage was studied with radioactive labels such as (42)K and (28)Mg. Bacteriophage-induced leakage was dependent on the ratio of phage to bacteria: the higher the multiplicity of infection, the greater the leakage. No leakage occurred at 4 C [when adsorption proceeds but injection of phage deoxyribonucleic acid (DNA) is blocked]. Leakage was caused by heavily irradiated phage as well as by normal phage; therefore, the intracellular functioning of the bacteriophage DNA was not required. This conclusion was supported by experiments which showed phage-induced leakage in the presence of chloramphenicol or sodium cyanide. Leakage could be prevented by infecting the bacteria with phage in the presence of high magnesium concentrations. Phage-induced leakage was terminated by a "sealing" reaction, after which potassium turnover by infected and uninfected cells was very similar. The sealing reaction occurred even in the presence of chloramphenicol, suggesting that the sealing is controlled by bacterial and not bacteriophage genes. We were not able to detect any effect of normal bacteriophage infection on the influx (active transport) of potassium and magnesium into the cells.

Adsorption↗