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Biomedical subjects

J M Goodman

Publications and source records attributed to J M Goodman.

At least 55 records · Page 3Linked to original sources
PubMed1997

Acute effects of cocaine on human brain activity and emotion.

We investigated brain circuitry mediating cocaine-induced euphoria and craving using functional MRI (fMRI). During double-blind cocaine (0.6 mg/kg) and saline infusions in cocaine-dependent subjects, the entire brain was imaged for 5 min before and 13 min after infusion while subjects rated scales for rush, high, low, and craving. Cocaine induced focal signal increases in nucleus accumbens/subcallosal cortex (NAc/SCC), caudate, putamen, basal forebrain, thalamus, insula, hippocampus, parahippocampal gyrus, cingulate, lateral prefrontal and temporal cortices, parietal cortex, striate/extrastriate cortices, ventral tegmentum, and pons and produced signal decreases in amygdala, temporal pole, and medial frontal cortex. Saline produced few positive or negative activations, which were localized to lateral prefrontal cortex and temporo-occipital cortex. Subjects who underwent repeat studies showed good replication of the regional fMRI activation pattern following cocaine and saline infusions, with activations on saline retest that might reflect expectancy. Brain regions that exhibited early and short duration signal maxima showed a higher correlation with rush ratings. These included the ventral tegmentum, pons, basal forebrain, caudate, cingulate, and most regions of lateral prefrontal cortex. In contrast, regions that demonstrated early but sustained signal maxima were more correlated with craving than with rush ratings; such regions included the NAc/SCC, right parahippocampal gyrus, and some regions of lateral prefrontal cortex. Sustained negative signal change was noted in the amygdala, which correlated with craving ratings. Our data demonstrate the ability of fMRI to map dynamic patterns of brain activation following cocaine infusion in cocaine-dependent subjects and provide evidence of dynamically changing brain networks associated with cocaine-induced euphoria and cocaine-induced craving.

Adult↗
PubMed1997

Resistance and aerobic training in older men: effects on VO2peak and the capillary supply to skeletal muscle.

Both aerobic training (AT) and resistance training (RT) may increase aerobic power (VO2peak) in the older population; however, the role of changes in the capillary supply in this response has not been evaluated. Twenty healthy men (age 65-74 yr) engaged in either 9 wk of lower body RT followed by 9 wk of AT on a cycle ergometer (RT-->AT group) or 18 wk of AT on a cycle ergometer (AT-->AT group). RT was performed three times per week and consisted of three sets of four exercises at 6-12 repetitions maximum. AT was performed three times per week for 30 min at 60-70% heart rate reserve. VO2peak was increased after both RT and AT (P < 0.05). Biopsies (vastus lateralis) revealed that the number of capillaries per fiber perimeter length was increased after both AT and RT (P < 0.05), paralleling the changes in VO2peak, whereas capillary density was increased only after AT (P < 0.01). These results, and the finding of a significant correlation between the change in capillary supply and VO2peak (r = 0.52), suggest the possibility that similar mechanisms may be involved in the increase of VO2peak after high-intensity RT and AT in the older population.

Aged↗
PubMed1996

Eadfrith: a molecular rendering program for Silicon Graphics workstations.

Eadfrith was written to provide the rapid display of molecules, so that they can be interactively rotated, translated, and scaled, and then rendered in a manner suitable for photography or other high-quality output methods. The program provides support for the display of transparency, electrostatic effects, and the normal vibrational modes of molecules. The compiled version for Silicon Graphics machines is freely available over the World-Wide Web. Eadfrith reads the structures from files in MacroModel format. The aim of the program is to provide a way to display molecular structures quickly and to produce high-quality pictures. Consequently, image-saving routines are not included, and standard utilities must be used in conjunction with Eadfrith to save the images to disk.

Computer Graphics↗
PubMed1996

The sorting sequence of the peroxisomal integral membrane protein PMP47 is contained within a short hydrophilic loop.

No targeting sequence for peroxisomal integral membrane proteins has yet been identified. We have previously shown that a region of 67 amino acids is necessary to target Pmp47, a protein that spans the membrane six times, to peroxisomes. This region comprises two membrane spans and the intervening loop. We now demonstrate that the 20 amino acid loop, which is predicted to face the matrix, is both necessary and sufficient for peroxisomal targeting. Sufficiency was demonstrated with both chloramphenicol acetyltransferase and green fluorescent protein as carriers. There is a cluster of basic amino acids in the middle of the loop that we predict protrudes from the membrane surface into the matrix by a flanking stem structure. We show that the targeting signal is composed of this basic cluster and a block of amino acids immediately down-stream from it.

Amino Acid Sequence↗
PubMed1996

Redox-sensitive homodimerization of Pex11p: a proposed mechanism to regulate peroxisomal division.

Pex11p (formerly Pmp27) has been implicated in peroxisomal proliferation (Erdmann, R., and G. Blobel. 1995. J. Cell Biol. 128; 509-523; Marshall, P.A., Y.I. Krimkevich, R.H. Lark, J.M. Dyer, M. Veenhuis, and J.M. Goodman, 1995. J. Cell Biol. 129; 345-355). In its absence, peroxisomes in Saccharomyces cerevisiae fail to proliferate in response to oleic acid; instead, one or two large peroxisomes are formed. Conversely, overproduction of Pex11p causes an increase in peroxisomal number. In this report, we confirm the function of Pex11p in organelle proliferation by demonstrating that this protein can cause fragmentation in vivo of large peroxisomes into smaller organelles. Pex11p is on the inner surface of the peroxisomal membrane. It can form homodimers, and this species is more abundant in mature peroxisomes than in proliferating organelles. Removing one of the three cysteines in the protein inhibits homodimerization. This cysteine 3-->alanine mutation leads to an increase in number and a decrease in peroxisomal density, compared with the wild-type protein, in response to oleic acid. We propose that the active species is the "monomeric" form, and that the increasing oxidative metabolism within maturing peroxisomes causes dimer formation and inhibition of further organelle division.

Base Sequence↗