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Biomedical subjects

R C Powell

Publications and source records attributed to R C Powell.

14 recordsLinked to original sources
PubMed1992

Comparison of holmium and flashlamp pumped dye lasers for use in lithotripsy of biliary calculi.

The characteristics of laser lithotripsy of biliary calculi are compared for a flashlamp pumped dye laser (lambda = 640 nm) and a Cr:Tm:Ho-YAG laser (lambda = 2.1 microns). Data on fragmentation efficiency with respect to laser power and pulse repetition rate are presented for different types of stones. It is shown that both lasers can produce effective stone fragmentation. The laser power required for efficient fragmentation characteristics is significantly less for the visible wavelength laser. However, the problems associated with damage to the fiber tips of the delivery system during operation were found to be less with the near infrared wavelength. The laser power for efficient fragmentation with the dye laser varies significantly for different types of stones while the power for efficient fragmentation with the holmium laser is the same for all stones.

Cholelithiasis↗
PubMed1988

Faculty and house staff members as role models.

In the fall of 1986 approximately 100 faculty members, community physicians, house staff members, and students associated with Indiana University School of Medicine participated in a conference on "Teachers as Role Models: The Impact on the Learning Process." Small-group discussions allowed the participants to define and discuss the impact of role-modeling in medical education. It was anticipated by the organizers that after the conference the participants would be more cognizant of their influence as role models and would be motivated to become better role models and support good role-modeling. A synopsis of the conference indicates that the participants identified both the positive and negative impact of role-modeling and concluded that medical educational programs should use positive role-modeling as a teaching tool to instill within students the desire to gain new knowledge and to apply that knowledge as medical professionals.

Education, Medical, Undergraduate↗
PubMed1988

Role modeling.

Explore the source record for details and available documents.

Education, Medical↗
PubMed1986

Diverse molecular forms of gonadotropin-releasing hormone in an elasmobranch and a teleost fish.

Immunoreactive and biologically active gonadotropin-releasing hormones (GnRHs) in dogfish (Poroderma africanum) and teleost (Coris julis) brain extracts were studied by high-performance liquid chromatography (HPLC), radioimmunoassay with region-specific antisera, and assessment of luteinizing hormone (LH)-releasing activity in a chicken dispersed pituitary cell bioassay. In dogfish brain extract, seven GnRH molecular forms with LH-releasing activity were demonstrated. Three of these forms coeluted with synthetic mammalian GnRH; His5,Trp7,Tyr8-GnRH; and Trp7,Leu8-GnRH on HPLC. The peaks coincident with His5,Trp7,Tyr8-GnRH and Trp7,Leu8-GnRH had immunological and biological properties identical to those of the synthetic peptides. However, the molecular form coeluting with mammalian GnRH had immunological and biological properties different from those of mammalian GnRH and is thus a novel molecular variant of GnRH. The four remaining forms are also novel GnRHs or structurally unrelated peptides with LH-releasing activity. Dogfish systemic blood contained immunoreactive GnRH. In teleost brain extract, three biologically active GnRH forms with LH-releasing activity were present. The major peak of GnRH immunoreactivity coeluted with Trp7,Leu8-GnRH, and a second immunoreactive form coeluted with His5,Trp7,Tyr8-GnRH. The third biologically active peak is a novel, early-eluting molecular variant of GnRH or a structurally unrelated peptide with LH-releasing activity.

Animals↗
PubMed1979

The "subliminal" versus the "subconscious" in the American acceptance of psychoanalysis, 1906-1910.

Insofar as Frederic W. H. Myers' conceptions of the "subliminal" were spread by the Boston-based "Emmanuel movement" for medically supervised religious psychotherapy (fl. 1906-1910), the movement probably did more to help than to hinder American acceptance of Freudian ideas. Certainly, many academic psychologists' conceptions of the "unconscious" and "subconscious" were a hindrance.

Austria↗
PubMed1978

Helen Flanders Dunbar (1902-1959) and a holistic approach to psychosomatic problems. II. The role of Dunbar's nonmedical background.

Despite Dunbar's central role in the American psychosomatic movement, few successors seem to have grasped the nature and context of her work. This is partially because, as conveyed in Part I of his article, most histories of psychosomatic theory and research overlook the holistic, organismic point of view shared by Dunbar and other psychoanalysts of the psychobilogic persuasion. However, to grasp the full meaning of Dunbar's work one must look to her nonmedical background in Dantean philosphy and in religious healing.

History, 20th Century↗
PubMed1977

Helen Flanders Dunbar (1902-1959) and a holistic approach to psychosomatic problems. I. The rise and fall of a medical philosophy.

Despite Dunbar's central in the American psychosomatic movement, few successors seem to have grasped the nature and context of her work. This is partially because most histories of psychosomatic theory and research overlook the holistic, organismic point of view shared by Dunbar and other psychoanalysts of the psychobiologic persuasion. The medical-philosophical context of Dunbar's work is here reviewed.

Attitude of Health Personnel↗
PubMed1977

Anton T. Boisen's "Psychiatric Examination: Content of Thought" (c. 1925-31): an attempt to grasp the meaning of mental disorder.

DURING the early years of PSYCHIATRY, the Rev. Dr. Anton T. Boisen (1876-1965) was among the journal's most regular contributors. Within 14 years he wrote eight articles and four book reviews for PSYCHIATRY, with many of these touching upon the psychosocial aspects of religious experience, empirically considered. Behind Boisen's fondness for PSYCHIATRY was his sense of special relationship to the founding editor, Harry Stack Sullivan. In some ways, this affinity to Sullivan and his world-view can best be appreciated by examining the hypotheses and research questionnaire Boisen used to develop the data for his articles. Likewise, a look at Boisen's detailed questionnaire may help us to understand how humanistic social scientists of an earlier era, the 1920s, attempted to grasp the meaning of mental disorder.

Clergy↗
PubMed1976

Variance of plasma free and esterified cholesterol in adult twins.

Total, free and esterified cholesterol were measured in the plasma, high density lipoproteins, low density lipoproteins, and total cholesterol in the very low density lipoproteins of 141 pairs of adult white male twins. Free cholesterol in plasma, high density lipoproteins and low density lipoproteins had significant genetic variance. Esterified cholesterol had greater total variance in dizygotic than monozygotic twins, interpreted as evidence for greater environmental influences on the two types of twins. After bias due to unequal environmental effects on the two types of twins was removed, there was no significant genetic variance for any esterified fraction of cholesterol.

Adult↗
PubMedDate not supplied

[Trp7,Leu8]LH-RH in reptilian brain.

Luteinizing hormone-releasing hormone (LH-RH) immunoreactive peptides in acetic acid extracts of lizard (Cordylis nigra) brain were studied by high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera. Four different LH-RH immunoreactive peptides were detected. The major form co-eluted with salmon brain LH-RH, [Trp7,Leu8]LH-RH, in a cation exchange and three reverse phase HPLC systems which were specifically designed to separate a range of LH-RH analogues. The interaction of this major LH-RH immunoreactive peptide with a number of antisera directed against different regions of mammalian, chicken and salmon LH-RH was similar to the relative interaction of [Trp7,Leu8]LH-RH with these antisera. These data strongly indicate that the major form of lizard brain LH-RH is identical to salmon brain LH-RH [( Trp7,Leu8]LH-RH). The three additional molecular forms of immunoreactive LH-RH in lizard brain appear to differ from mammalian LH-RH in the middle to C-terminal region of the molecule.

Animals↗
PubMedDate not supplied

Identification of diverse molecular forms of GnRH in reptile brain.

Gonadotropin-releasing hormone (GnRH) molecular forms in the brains of three reptiles, Alligator mississippiensis (alligator), Calcides ocellatus tiligugu (skink) and Podarcis s. sicula (lizard) were characterized by high performance liquid chromatography (HPLC) and radioimmunoassay with region-specific antisera, and by assessment of luteinizing (LH)-releasing activity in chicken dispersed pituitary cells. In alligator brain two GnRHs had identical properties to the two known forms of chicken hypothalamic GnRH (Gln8-GnRH and His5,Trp7,Tyr8-GnRH) in their elution on two reverse phase HPLC systems, cross-reaction with region-specific GnRH antisera, and ability to release LH. In skink brain, one immunoreactive and bioactive GnRH form, which eluted in the same position as His5,Trp7,Tyr8-GnRH on reverse phase HPLC, was identified. Three bioactive and immunoreactive GnRHs were detected in lizard brain. One form had similar properties to salmon brain GnRH (Trp7,Leu8-GnRH). The other two GnRH-like peptides are novel forms. One of these forms eluted in the same position as Gln8-GnRH on HPLC but had different immunological properties, while the third form was a rather hydrophobic species which appeared to be modified in the middle region of the molecule.

Alligators and Crocodiles↗
PubMedDate not supplied

Identification of Gln8-GnRH and His5,Trp7,Tyr8-GnRH in the hypothalamus and extrahypothalamic brain of the ostrich (Struthio camelus).

Gonadotropin-releasing hormone (GnRH) molecular forms were studied in extracts of ostrich hypothalamus and extrahypothalamic brain using high performance liquid chromatography, radioimmunoassay with region-specific antisera and assessment of luteinizing hormone (LH)-releasing activity using chicken dispersed pituitary cells. Two molecular forms of GnRH with chromatographic, immunological and biological properties identical to those of Gln8-GnRH and His5,Trp7,Tyr8-GnRH were demonstrated in both the hypothalamic and extrahypothalamic brain extracts. A greater proportion of His5,Trp7,Tyr8-GnRH was present in the hypothalamus than in extrahypothalamic brain. It is likely that these two forms of GnRH are present in all bird species, since the chicken and the ostrich have evolved separately.

Animals↗