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Biomedical subjects

J Farber

Publications and source records attributed to J Farber.

At least 37 records · Page 2Linked to original sources

Rapid eye movement sleep PGO-type waves are present in the dorsal pons of the albino rat.

We have found rapid eye movement sleep central phasic activity in the form of episodic, repetitive, monophasic waves in the albino rat. This activity is recorded in discrete areas of the dorso-lateral pons, including the nucleus locus ceruleus. The vast majority of these waves occur during rapid eye movement sleep. Their distribution and electrophysiological characteristics are similar to those of ponto-geniculo-occipital waves in the cat.

Animals↗

Harm-doing and victim's racial or orthopedic stigma as determinants of helping behavior.

Three experiments tested a prediction derived from an ambivalence theory of behavior toward the stigmatized. The prediction was that unintentional harm-doers would be more likely to make restitution by doing a favor for a stigmatized victim than for a nonstigmatized one. In Experiment 1 it was upheld for black versus white victims. In Experiment 2, where the victim of harm-doing was either physically handicapped or normal, the prediction was upheld only among older subjects, following the post hoc introduction of an age variable. Experiment 3 also used a physical disability variable. The data were consistent with the prediction, although the adequacy of the harm-doing manipulation was not checked empirically. On the whole, these results are seen as complementing previous findings of amplified post-harm-doing denigration of black and disabled victims. An assumption that the relationship between harm-doing and altruism was mediated by guilt arousal received only fragmentary support. That is, self-reports of guilt were highest in the harm-doing black confederate condition in Experiment 1, and self-reports of negative affect were highest in the harm-doing/wheelchair confederate condition in Experiment 3, but there were no significant relationships between individual differences in guilt or negative affect on the one hand, and amount of helping, on the other.

Adolescent↗

Geometric transformations of pictured space.

In general, a picture can represent a specific environment of scene only when the picture is seen from a unique viewing point. The determination of this unique point and of the distortions that occur when the picture is viewed from other points is crucial to all aspects of pictorial perception. To clarify the effects of the point of observation on pictorial space, the present paper discusses how the correct point may be calculated, provides a geometric analysis of the effects of altering the viewing point, and briefly reviews the effects of such alterations on space perception.

Depth Perception↗

When courtesy offends: effects of positive and negative behavior by the pbysically disabled on altruism and anger in normals.

The initial hypothesis was that physically disabled help-seekers will receive more aid from normal people than will help-seekers when both types of actors display positive personal qualities, whereas the reverse outcome will occur when both display negative qualities. In the first experiment a wheelchair-bound or normal confederate was either friendly and achievement oriented (positive condition) or caustic and apathetic (negative condition) while administering verbal tasks to subjects who were later asked to help the confederate. Contrary to prediction, subjects offered more help to the normal than to the disabled tester in the positive condition, and showed the reverse pattern in the negative condition. It was conjectured that subjects in the positive condition were annoyed by the disabled person's display of "normal" characteristics, whereas in the negative condition they sympathetically accepted the disabled person's inadequacies as befitting a victim of severe misfortune. A new experiment was done, which replicated the independent variables of the first study, but substituted two new dependent variables: covert anger arousal and perception of the confederate as happy-unhappy. As expected, covert anger was greater in the wheelchair-positive condition than in the normal-positive condition, and greater in the normal-negative condition than in the wheelchair-negative condition. Regardless of the confederate's physical status, subjects perceived negative behavior as a sign of unhappiness.

Adolescent↗

Role of nonhistone chromosomal proteins in the restriction of mitotic chromatin template activity.

RNA synthesis virtually ceases during mitosis in eukaryotic cells. This phenomenon is explainable, at least in part, by the reduced template activity for RNA synthesis of mitotic chromatin. The restriction in template activity can be accounted for by the presence in the chromatin of mitotic-specific nonhistone proteins. Chromatin reconstituted by gradient dialysis from the pooled histones of S-phase and mitotic chromatin and the nonhistone proteins of mitotic chromatin had a template activity similar to that of native mitotic chromatin, and lower than native S-phase chromatin or chromatin reconstituted with the pooled histones and the S-phase and nonhistone proteins. The template activity was identical for chromatin reconstituted from the pooled nonhistone proteins and either the histones from S-phase or mitotic chromatin. These results are supported with data showing that the procedure of reconstitution produces a chromatin indistinguishable in its protein composition both qualitatively and quantitatively from its native counterpart.

Carbon Isotopes↗

Template activity of chromatin during stimulation of cellular proliferation in human diploid fibroblasts.

1. Contact-inhibited confluent monolayers of WI-38 human diploid fibroblasts can be stimulated to divide by replacing the medium with fresh medium containing 30% foetal calf serum. 2. Of the cells 40-75% are stimulated to divide with a peak DNA synthesis between 15 and 21h and a peak mitotic index between 28 and 30h after stimulation. 3. In the first 12h before the initiation of DNA synthesis there is a biphasic increase in the incorporation of [(3)H]uridine into RNA of whole cells. 4. This is paralleled by a similar biphasic stimulation of chromatin template activity measured in vitro in a system in which purified cell chromatin is incubated with an exogenous RNA polymerase isolated from Escherichia coli. 5. The changes in chromatin template activity are believed to represent activation of the genome, with more sites available for RNA synthesis, and to account almost entirely for the changes in RNA synthesis occurring in the whole cell.

Animals↗

Gene activation in WI-38 fibroblasts stimulated to proliferate: requirement for protein synthesis.

Confluent monolayers of WI-38 human diploid fibroblasts can be stimulated to divide by fresh medium containing 30% fetal-calf serum. Up to 80% of the cells are stimulated to divide, with a peak of DNA synthesis between 15 and 21 hr. 1 hr after the change of medium there is a 70% rise in chromatin template activity. Cycloheximide inhibited the increase in chromatin template activity. A requirement for RNA synthesis was investigated by incubating stimulated and unstimulated cells with 10 mug/ml of actinomycin D. In spite of a 95% inhibition of RNA synthesis in whole cells, purified chromatin from stimulated cells showed the usual increase in template activity. These experiments implicate a requirement for protein synthesis in template activation, and imply that the synthesis of this (or these) protein(s) is independent of RNA synthesis and regulated by a purely translational mechanism.

Autoradiography↗

Regulation of acetylcholinesterase in neuroblastoma cells.

The specific activity of mouse neuroblastoma acetylcholinesterase (EC 3.1.1.7) increased 25-fold when the rate of cell division was restricted. The results show that acetylcholinesterase activity is regulated in neuroblastoma cells and that the regulatory mechanism is inversely related to the rate of cell division. Under the same conditions the specific activity of catechol-O-methyl transferase (EC 2.1.1.6) did not change significantly.

Acetylcholinesterase↗