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Biomedical subjects

D Goodman

Publications and source records attributed to D Goodman.

At least 91 records · Page 5Linked to original sources
PubMed1979

On the nature of human interlimb coordination.

Movement time varies as a function of amplitude and requirements for precision, according to Fitts' law, but when subjects perform two-handed movements to targets of widely disparate difficulty they do so simultaneously. The hand moving to an "easy" target moves more slowly to accommodate its "difficult" counterpart, yet both hands reach peak velocity and acceleration synchronously. This result suggests that the brain produces simultaneity of action not by controlling each limb independently, but by organizing functional groupings of muscles that are constrained to act as a single unit.

Adult↗
PubMed1979

On the coordination of two-handed movements.

In a set of three experiments, we show that after an auditory "go" signal, subjects simultaneously initiate and terminate two-handed movements to targets of widely disparate difficulty. This is the case when the movements required are (a) lateral and away from the midline of the body (Experiment 1), (b) toward the midline of the body (Experiment 2), and (c) in the forward direction away from the body midline (Experiment 3). Kinematic data obtained from high-speed cinematography (200 frames/sec) point to a tight coordinative coupling between the two hands. Although the hands move at entirely different speeds to different points in space, times to peak velocity and acceleration are almost perfectly synchronous. We believe that the brain produces simultaneity of action as the optimal solution for the two-handed task by organizing functional groupings of muscles (coordinative structures) that are constrained to act as a single unit.

Adolescent↗
PubMed1979

Movement coding and memory in retarded children.

Three experiments on the coding and retention of movement-generated information were performed on two groups of mildly retarded children varying in MA. The cue to be reproduced in each case was the terminal position of the limb that studies with adults have shown to require central processing activity for maintained performance. In Experiment 1, although the older MA group was superior, both groups showed similar decrements in performance over a 15-second retention interval. In Experiment 2 the procedures were adopted in an attempt to overcome performance deficits. Subjects were allowed to choose (preselect) their own movements voluntarily in addition to performing constrained, experimenter-defined movements. Preselected reproduction was superior to constrained at all three retention intervals (0, 7, and 15 seconds) but was not statistically different among age groups. Also, performance was maintained for both groups over 7 seconds but deteriorated over 15 seconds. These results were replicated in Experiment 3, which also showed that an interpolated motor task designed to block rehearsal processes interfered with reproduction at the 7- and 15-second retention-interval conditions. The findings indicated that mildly retarded children could maintain motor information over brief time periods and also illustrated the important contribution of the planning component in facilitating the coding of motoric information.

Adolescent↗
PubMed1976

Purification and characterization of L-asparaginase with anti-lymphoma activity from Vibrio succinogenes.

Homogeneols L-asparaginase with anti-lymphoma activity was prepared from Vibrio succinogenes, an anaerobic bacterium from the bovine rumen. An overall yield of pure L-asparaginase of 40 to 45% and a specific activity of 200 +/- 2 IU per mg of protein was obtained. The pure enzyme can be stored at -20 degrees for at least 3 months with no loss of activity. The isoelectric point of the L-asparaginase is 8.74. No carbohydrate, phosphorus, tryptophan, disulfide, or sulfhydryl groups were detected. The enzyme has a molecular weight of 146,000 and a subunit weight of approximately 37,000. The Km of the enzyme for L-asparagine is 4.78 X 10(-5) M and the pH optimum of the L-asparaginase reaction is 7.3. D-Asparagine was hydrolyzed at 6.5% of the rate found with the L isomer. L-Glutamine and a variety of other amides were not hydrolyzed at significant rates; the activity of the enzyme for L-glutamine was 130- to 600-fold less than that of other therapeutically effective L-asparaginases of bacterial origin. The L-asparaginase from V. succinogenes is immunologically distinct from the L-asparaginase (EC-2) of Escherichia coli.

Animals↗
PubMed1974

L-Asparaginase production by the rumen anaerobe Vibrio succinogenes.

The rumen anaerobe Vibrio succinogenes possesses a constitutive L-asparaginase. The amount of enzyme produced is affected by the compound supplied to the organism to generate the fumaric acid it requires as a terminal electron acceptor. When nitrate is provided as the terminal electron acceptor, the amount of enzyme produced is affected by the compound provided to satisfy the nutritional requirement of the organism for succinic acid. Specific activities of up to 8.4 IU/mg of protein in cell-free extracts have been obtained. This specific activity is higher than has been previously reported for any organism. The enzyme has an apparent K(m) of 1.7 x 10(-5) M and low activity towards L-glutamine when assayed at pH 8.5.

Anaerobiosis↗