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Biomedical subjects

J Farley

Publications and source records attributed to J Farley.

90 records · Page 5Linked to original sources
PubMed1980

Neural organization predicts stimulus specificity for a retained associative behavioral change.

Paired, but not random, presentations of light and rotation produced long-term changes in Hermissenda's response to light. The nature of this change depended on the orientation of the animals with respect to the center of rotation and was predicted by known organizational features of Hermissenda's nervous system. When rotation that excited caudal hair cells was paired with light, a significant increase in response latency to test lights resulted. Rotation exciting cephalic hair cells when paired with light decreased the response latencies compared with latencies produced by random presentation of light and rotation.

Animals↗
PubMed1980

Reinforcement and punishment effects in concurrent schedules: A test of two models.

The joint effects of punishment and reinforcement on the pigeon's key-peck response were examined in three choice experiments conducted to compare predictions of Farley and Fantino's (1978) subtractive model with those made by Deluty's (1976) and Deluty and Church's (1978) model of punishment. In Experiment 1, the addition of equal punishment schedules to both alternatives of a concurrent reinforcement schedule enhanced the preference exhibited for the more frequent reinforcement alternative. Experiment 2 demonstrated decreases in the absolute response rate for each member of a concurrent reinforcement schedule when increasing frequencies of punishment were added to each alternative. Experiment 3 found that preference for the denser of two reinforcement schedules diminished when the absolute frequencies of reinforcement were increased by a constant factor and conditions of punishment for both alternatives were held constant. Diminished preferences were obtained regardless of whether the frequency of punishment associated with the denser reinforcement schedule was greater or less than that associated with the lean reinforcement alternative. The results from all three experiments uniquely supported Farley and Fantino's (1978) subtractive model of punishment and reinforcement.

Journal Article↗
PubMed1980

A report on two interlaboratory surveys of serum ferritin estimation.

Two surveys of the proficiency of performance of serum ferritin estimation in Australia have been conducted, one in 1978 and one in 1979. The majority of participants in both surveys used assay kits supplied by Clinical Assays, Roche Diagnostics and Ramco. The first survey showed a median intrabatch variation 9% and median interbatch variation of 17%. The overall assay variation had a median level of 22%. Assays by the various kits gave values which were not significantly different for each specimen (including purified liver and spleen ferritin solutions). The second survey showed an improvement in the overall precision of the participants with a median coefficient of variation of 15%. Contrary to the first survey, significant differences were evident between the results in 4 of the 5 specimens assayed. Some participants returned results for the high ferritin serum that differed substantially depending on the dilution of the sample used. The surveys showed a need for improvement in the assay performance of some participants, the need for ferritin levels to be assayed at least in two dilutions, and the need for standardization of assays, reference ranges and reporting units. Recommendation are made on all these points.

Ferritins↗
PubMed1978

The symmetrical law of effect and the matching relation in choice behavior.

In a concurrent-chains procedure, pigeons chose between outcomes that differed in the rate of response-independent delivery of food and electric shocks. The application of functional measurement techniques confirmed the matching relation-between choice and rate of reinforcement value-for two of three pigeons. Scale values of the outcomes were extracted for the two birds that conformed to matching, and the value of a single occurrence of shock per minute-in terms of negative food units-was estimated. A second experiment with concurrent chains provided a test of these parameter estimates. The close correspondence between predicted and obtained choice behavior found in Experiment II indicated that the estimates of outcome value were indeed reliable. Both experiments together support the contention that the effects on choice behavior of positive and aversive stimuli appear to be equal, though opposite in sign.

Journal Article↗
PubMedDate not supplied

Protein kinase C activation induces conductance changes in Hermissenda photoreceptors like those seen in associative learning.

Phosphorylation of ion channels has been suggested as one molecular mechanism responsible for learning-produced long-term changes in neuronal excitability. Persistent training-produced changes in two distinct K+ currents (IA (ref. 2), IK-Ca (refs 3,4)) and a voltage-dependent calcium current (ICa; refs 3,4) have previously been shown to occur in type B photoreceptors of Hermissenda, as a result of associative learning. But the identity of the phosphorylation pathway(s) responsible for these changes has not as yet been determined. Injections of cyclic AMP-dependent protein kinase reduce a K+ current (IK) in B cells which is different from those changed by training, but fails to reduce IA and IK-Ca. Phosphorylase b kinase (an exogenous calcium/calmodulin-dependent kinase) reduces IA, but whether IK-Ca and ICa are changed in the manner of associative training is not yet known. Another protein kinase present in high concentrations in both mammalian brain and molluscan nervous systems is protein kinase C, which is both calcium- and phospholipid-sensitive. We now present evidence that activation of protein kinase C by the tumour promoter phorbol ester (PDB) and intracellular injection of the enzyme induce conductance changes similar to those caused by associative training in Hermissenda B cells (that is a reduction of IA and IK-Ca, and enhancement of ICa). These results represent the first direct demonstration that protein kinase C affects membrane K+ ion conductance mechanisms.

Animals↗
PubMedDate not supplied

Evaluation of epoxy ether fixed bovine arterial grafts for mutagenic potential.

Two epoxy ether compounds [glycerol polyglycidyl ether (Denacol EX-313) and ethylene glycol diglycidyl ether (Denacol EX-810)] are under consideration as alternatives to glutaraldehyde for use in the processing of an arterial graft. The two are utilized as cross-linking and sterilant agents, respectively. Epoxy resins are multifunctional alkylating agents, and bifunctional alkylating epoxide solutions are known to be mutagenic. The correlation between mutagenic potential and carcinogenicity, in addition to evidence that diepoxides are carcinogenic in mice and rats, prompted the evaluation of the mutagenic potential of the epoxy treated, clinically rinsed graft. Ames and sister chromatid exchange (SCE) test procedures were used to assess mutagenic potential. Normal saline and distilled water were selected as the most physiologically representative and procedurally acceptable extraction mediums for the Ames and SCE tests, respectively. The results of the Ames and SCE tests in both the activated and non activated systems indicated that there were no statistically significant differences detected between various test article concentrates and the spontaneous mutation controls for both the activated and non activated systems. The epoxy treated graft was determined to be non mutagenic and demonstrated no dose related responses by these methods.

Animals↗