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Biomedical subjects

R Schafer

Publications and source records attributed to R Schafer.

At least 55 records · Page 3Linked to original sources
PubMed1988

Calcium and olfactory transduction.

1. Inorganic cations, organic calcium antagonists, and calmodulin antagonists were applied to olfactory epithelia of frogs (Rana pipiens) while recording electroolfactogram (EOG) responses. 2. Inorganic cations inhibited EOGs in a rank order, reflecting their calcium channel blocking potency: La3+ greater than Zn2+ greater than Cd2+ greater than Al3+ greater than Ca2+ greater than Sr2+ greater than Co2+ greater than Ba2+ greater than Mg2+. Barium ion significantly enhanced EOGs immediately following application. 3. Diltiazem and verapamil produced dose-dependent EOG inhibition. 4. Calmodulin antagonists inhibited EOGs without correlation to their anti-calmodulin potency.

Animals↗
PubMed1987

Inhibition of protein synthesis does not block physiological responses to odors in the frog over the short term.

Frog olfactory mucosae were stimulated with an odorant every 60 sec and electrophysiological responses (electroolfactograms or EOGs) were monitored continuously--before, during, and after treatment with puromycin, a protein synthesis inhibitor. Repeated administration of puromycin at 4 hr intervals over a 36 hr period failed to suppress EOG responses. In an alternative approach, olfactory responses were inhibited with ethyl bromoacetate, a vaporous alkylating agent. EOG responses failed to reappear over a 72 hr period. We conclude that receptor turnover is not readily influenced by stimulation, and that the turnover time of frog olfactory receptor proteins is of the order of days or longer.

Animals↗
PubMed1985

Wild analysis.

Contemporary debates over psychoanalytic theory and practice warrant a reconsideration of the concept of wild analysis. Freud's initial formulation of the problem, subsequent developments in the Freudian conventions, and the work of Melanie Klein, Kohut, and Gill are compared in order to bring out different conceptions of interpretation that is wild, sound, or too tame. These different conceptions are system-bound. Moral implications of Klein's, Kohut's, and Gill's critiques and alternative systems are taken up.

Anxiety Disorders↗
PubMed1983

Effects of extracts of Trypanosoma cruzi on immune responses: induction of a nonspecific suppressor factor.

Extracts of epimastigotes of Trypanosoma cruzi were examined for the ability to augment or suppress in vivo and in vitro responses of mouse spleen cells. When administered to mice 4 days before immunization with sheep erythrocytes, the 12,000 X g pellet and the 104,000 X g pellet and supernatant fractions of extracts of T. cruzi had no effect on the subsequent plaque-forming cell responses. Testing of the two 104,000 X g fraction in vitro resulted in a slight dose-dependent modification of anti-sheep erythrocyte responses. Also, these two fractions had a moderate dose-dependent blastogenic effect on normal spleen cells. Most significantly, the 104,000 X g supernatant fraction elicited the production of a suppressor factor when incubated with spleen cells from infected mice. This suppressor factor was also apparent when spleen cells from infected mice were incubated with intact epimastigotes or trypomastigotes. Production of the suppressor factor was insensitive to indomethacin and, therefore, presumably was not a prostaglandin.

Animals↗
PubMed1982

More than one-third of the discernible mouse polypeptides are not expressed in a Chinese hamster-mouse embryo fibroblast hybrid that retains all mouse chromosomes.

Gene expression at the level of polypeptide synthesis has been investigated in a somatic cell hybrid (20 BW-4) isolated after fusion of spontaneously transformed, tumorigenic Chinese hamster lung fibroblasts with mouse embryo fibroblasts. This hybrid exhibited suppression of tumorigenicity and retained--in addition to the parental Chinese hamster genome--copies of all mouse chromosomes as demonstrated by direct karyotype analysis and confirmed for 18 different mouse chromosomes by analysis of 18 different mouse isozymes. Two-dimensional gel electrophoresis of [35S]methionine-labeled polypeptides from hybrid 20 BW-4 showed that the overall polypeptide pattern corresponded to that of the hamster parent. All polypeptides detected in the hamster parental cells were also expressed in the hybrid although some of them were expressed in altered amounts. Of approximately 1200 labeled polypeptides revealed in the parental cells, 115 mouse polypeptides could be clearly distinguished from the hamster polypeptides due to their different electrophoretic mobilities. Forty-two of these (i.e., 37%) were not expressed in the hybrid 20 BW-4. These observations were confirmed by analysis of another independently isolated hybrid (2W 23) of the same parental cells that also exhibited suppression of malignancy and that retained copies of all mouse chromosomes except no. 5. The results suggest that the genome of the tumorigenic cell after hybridization can suppress expression of more than one-third of the normal parental genome. The suppressed mouse genetic information is probably located on many, if not all, different mouse chromosomes. Even if the level of genetic suppression is high the mouse genome is able to reduce the tumorigenicity of the hamster parental cell.

Animals↗
PubMed1982

The relevance of the 'here and now' transference interpretation to the reconstruction of early development.

The analytic process is presented as the construction, reconstruction, and interpenetration of narratives concerning the present as well as the past. No 'facts of the case' are given, all are mediated by constructions of the analysand and analyst. Through the narrative search for repetitions, and as a means of establishing the transference neurosis, the analyst retells both the present and the past in ever more co-ordinated and condensed fashion, thereby actualizing the timelessness of unconscious mental activity in the here-and-now analytic transference. The selection from the plenitude of narrative possibilities inherent in the analytic content is guided and controlled by the analyst's theoretical orientation and the analysand's responsiveness to the analyst's interventions. In the end, the analytic life history and the history of the analysis are constituted by an intermingling of observation and theory, subject and object, and present and past. A brief clinical illustration is included.

Child Development↗
PubMed1981

Colchicine reversibly inhibits electrical activity in arthropod mechanoreceptors.

Colchicine and some other microtubule-active agents inhibit the electrical responses of cockroach tibial spine mechanoreceptors. Lumicolchicine, a colchicine analog which does not bind to microtubule protein, does not inhibit mechanoreceptive responses. Colchicine inhibition of peripheral mechanoreceptive responses is fully reversible and dose dependent, but colchicine has no effect on conduction in leg nerve axons. Colchicine inhibition is therefore an effect on the sensory dendrites or soma. The inhibition produced by colchicine could be produced by several effects. Colchicine may inhibit because it (1) disrupts the numerous intracellular microtubules which are a part of this sensory receptor's dendrite, (2) blocks axoplasmic transport of essential materials to the sensory dendrite, or (3) binds to tubulin or other proteins in the dendritic membrane.

Animals↗
PubMed1977

The nature and development of sex attractant specificity in cockroaches of the genus Periplaneta. IV. electrophysiological study of attractant specificity and its determination by juvenile hormone.

The antennae of male Periplaneta americana acquire a large number of olfactory receptors at the adult stage. Electrophysiological methods (single unit and electroantennogram recording) show that a portion of the receptors added at the adult ecdysis are sex attractant receptors. Sex attractant receptors are not present in large numbers on larval and adult female antennae. The differentiation of pheromone receptors is inhibited during normal larval development by juvenile hormone. Topical application of juvenile hormone-mimic to male antennae during the terminal larval instar inhibits their development. Comparative electrophysiological studies indicate a high degree of cross-reactivity of the P. americana sex attractant among four other species within the genus Periplaneta.

Action Potentials↗
PubMed1977

Psychoanalytic methodology in Helene Deutsch's the psychology of women.

Although Helen Deutsch's The Psychology of Women contains a wealth of descriptive material about women's problems, the methodology employed by Deutsch in reaching her conclusions about femininity is marred in several ways. Her evolutionary-adaptational bias and natural science approach led to the attribution of questionable biological bases to behavior and to the neglect of social factors and learning. Her concepts and language reveal an unquestioning adoption of Freud's metapsychology and lead to a perception and interpretation of psychological events according to the specific cast of that approach. She confuses her values with definition and observation. A re-examination of the thought of Deutsch seems fitting in these days of ever more extensive reconsideration of the views of Freud and other major psychoanalytic thinkers on the psychology of women. In addition to furthering our understanding of her insights, the study of Deutsch's methodology and its pitfalls contributes to a more critical understanding of the values and preconceptions that influence popular thinking about women and to a deeper grasp of problems inherent in psychoanalytic methodology.

Adaptation, Psychological↗