Biomedical subjects

E A Hanna

Publications and source records attributed to E A Hanna.

16 recordsLinked to original sources

PubMed2001

Properties and modulation of alpha human atrial natriuretic peptide (alpha-hANP)-formed ion channels.

Using the lipid bilayer technique we have optimized recording conditions and confirmed that alpha human atrial natriuretic peptide [alpha-hANP(1-28)] forms single ion channels. The single channel currents recorded in 250/50 mM KCl cis/trans chambers show that the ANP-formed channels were heterogeneous, and differed in their conductance, kinetic, and pharmacological properties. The ANP-formed single channels were grouped as: (i) H202- and Ba2+-sensitive channel with fast kinetics; the nonlinear current-voltage (I-V) relationship of this channel had a reversal potential (Erev) of -28.2 mV, which is close to the equilibrium potential for K+ (EK = -35 mV) and a maximal slope conductance (gmax) of 68 pS at positive potentials. Sequential ionic substitution (KCl, K gluconate and choline Cl) of the cis solution suggests that the current was carried by cations. The fast channel had three modes (spike mode, burst mode, and open mode) that differed in their kinetics but not in their conductance properties. (ii) A large conductance channel possessing several subconductance levels that showed time-dependent inactivation at positive and negative membrane potentials (Vm). The inactivation ratio of the current at the end of the voltage step (Iss) to the initial current (Ii) activated immediately after the voltage step, (Iss/Ii), was voltage dependent and described by a bell-shaped curve. The maximal current-voltage (I-V) relationship of this channel, which had an Erev of +17.2 mV, was nonlinear and the value of gmax was 273 pS at negative voltages. (iii) A transiently-activated channel: the nonlinear I-V relationship of this channel had an Erev of -29.8 mV and the value of gmax was 160 pS at positive voltages. We propose that the voltage-dependence of the ionic currents and the kinetic parameters of these channel types indicate that if they were formed in vivo and activated by cytosolic factors they could change the membrane potential and the electrolyte homeostasis of the cell.

Amino Acid Sequence↗

PubMed1999

Gap junctional intercellular communication and connexin43 expression in human ovarian surface epithelial cells and ovarian carcinomas in vivo and in vitro.

Gap junctional intercellular communication (GJIC) and the expression of gap junction proteins (connexins) are frequently decreased in neoplastic cells and have been increased by cAMP and retinoids. GJIC and connexin expression were investigated in early passage normal human ovarian surface epithelial (HOSE) cells, human ovarian adenocarcinoma cell lines (CaOV-3, NIH:OVCAR-3, SK-OV-3 and SW626) and surgical specimens of human serous cystadenocarcinomas. We hypothesized that GJIC and connexin expression would be decreased in neoplastic cells and would be increased by cAMP and retinoic acid. Cultured HOSE cells exhibited extensive fluorescent dye-coupling and connexin43 (Cx43) expression; other connexins were not detected. The ovarian adenocarcinoma cell lines had little dye-coupling or connexin expression. Deletions and rearrangements of the Cx43 gene were not detected by Southern blotting in the carcinoma lines. N6, 2'-O-dibutyryladenosine 3',5'-cyclic monophosphate and all-trans-retinoic acid inhibited cell proliferation, but did not enhance GJIC or Cx43 expression. Surface epithelial cells of benign ovaries expressed Cx43, but this expression was barely detectable in ovarian serous cystadenocarcinomas. Thus, normal HOSE cells had extensive GJIC and Cx43 expression whereas ovarian carcinoma cells had less and cAMP and retinoic acid did not change these, although both agents inhibited cell growth.

Adenocarcinoma↗

PubMed1980

Extraperitoneal perirectal extravasation of barium during a barium enema examination: natural course and treatment.

Sixty cases of extraperitoneal intramural and perirectal extravasation of barium during a barium enema examination are reviewed. Approximately half the patients were asymptomatic and of these only one experienced serious complications. In the remaining patients, symptoms included pain, bleeding, fever, sepsis, mass and/or discharge. Morbidity and mortality was considerable despite aggressive treatment in many cases. Delay of treatment resulted in increase mortality and morbidity.

Adult↗

PubMed1979

An integration of psychosocial concepts into the education of general practitioners.

Psychosocial concepts related to human growth and development, doctor-patient interactions, and the professional use of self were integrated into a course for general practice residents which was taught by an interdisciplinary team. The content of the course was divided into two sections: theoretical and applied. In the first part of the course, residents were exposed in a relatively structured way to a health-oriented epigenetic perspective of the human condition. This framework was discussed with a view toward increasing assessment and intervention skills. In the latter half of the course, residents' owen case material was used to stimulate discussion of affective blocks to the use of self in the doctor-patient relationship. It was the purpose of this course to foster a total person approach to patient presentations.

Curriculum↗

PubMed1979

Potential sources of anxiety and depression associated with athletic competition.

The major purpose of this paper is to explore some tentative hypotheses concerning the relationship between the athlete's personal (internal) vulnerability and the realistically induced stress of world class competition. Clinically-oriented psychodynamic theory provides the theoretical underpinnings for this exploration. First, the positive, and particularly the negative impart of anxiety and depression on athletic performance is discussed. Then, for purposes of demonstrating the potential applications of clinically-oriented theory, a composite case example is offered illustrating the manner in which an athlete's internal vulnerability could lead to performance inhibitions. Finally, some tentative formulations are offered with a view towards correctively intervening with athletes whose natural capacity to cope with stress is temporarily outstripped, leading to inhibited performance.

Anxiety↗

PubMed1970