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Biomedical subjects

G J Creed

Publications and source records attributed to G J Creed.

24 records · Page 2Linked to original sources
PubMed1984

Proteins in normal, irradiated, and postmortem human brain quantitatively compared by using two-dimensional gel electrophoresis.

Using a combination of two-dimensional gel electrophoresis (2DE), silver staining, and computerized densitometry, we studied protein patterns in human cerebral cortex: normal fresh-frozen, fresh-frozen but previously irradiated, and post-mortem. The relative molecular mass of the resolved proteins ranged from 14 400 to 100 000, the isoelectric points from 4.75 to 7.0. The pattern of proteins (six of them identified) was essentially the same for all three groups. However, computerized densitometry demonstrated significant alterations in the density of several spots in the irradiated and postmortem groups as compared with the normal controls. Irradiated cortex showed statistically significant changes in only six spots (three increased and three decreased in density); postmortem material showed 20 altered spots (16 diminished and four increased). Evidently normal human cerebral cortex has a consistent protein pattern on 2DE, which is quantitatively (but not qualitatively) altered in irradiated and postmortem material. These findings provide a point of reference against which proteins from abnormal brain material can be compared, both qualitatively and quantitatively.

Cerebral Cortex↗
PubMed1983

Lesions of the paraventricular nucleus area of the hypothalamus disrupt the suprachiasmatic leads to spinal cord circuit in the melatonin rhythm generating system.

The circadian rhythm in melatonin production in mammals is regulated by a suprachiasmatic (SCN) leads to spinal cord leads to pineal circuit. In the present investigation the possible participation of the paraventricular nucleus of the hypothalamus (PVN) in the SCN leads to spinal cord segment of this circuit was investigated in the rat. Bilateral lesions of the PVN area were produced and one to two weeks later melatonin production was evaluated by measuring the activities of the two pineal enzymes required for the formation of melatonin from serotonin, indoleamine N-acetyltransferase (NAT) and hydroxyindole-O-methyltransferase (HIOMT), and urinary 6-hydroxymelatonin, the major melatonin metabolite. In some cases pineal melatonin was also measured. Control animals received sham-PVN lesions. Histological examination of the lesions indicated that the PVN were bilaterally destroyed 100% in 12 animals. The nighttime pineal melatonin and urinary 6-hydroxymelatonin values in this group were reduced about 90%, nighttime pineal NAT activity was reduced about 98%, and HIOMT activity about 75%. The urinary 6-hydroxymelatonin values of PVN-lesioned animals and animals with denervated pineal glands were similar. In animals with hypothalamic lesions involving less than 30% of the PVN, nighttime values of NAT, HIOMT, and urinary 6-hydroxymelatonin were normal; in animals with 30 to 95% PVN damage these parameters were altered to a small degree. These studies, together with histochemical observations, indicate the SCN neurons responsible for pineal circadian rhythms project to the PVN area of the hypothalamus.

Acetylserotonin O-Methyltransferase↗
PubMed1983

Cholinergic projection sites of the nucleus of tractus diagonalis.

The cholinergic projection sites of the basal portion of the nucleus of the tractus diagonalis (td) were studied following bilateral stereotaxic lesions. Choline acetyltransferase (ChAT) activity was measured in various cortices, hippocampus and amygdala. Significant decreases in ChAT activity were observed in the anterior and posterior cingulate cortex, the frontal cortex, occipital cortex, hippocampus and dentate gyrus. It is concluded that (1) the hippocampus is innervated by the basal portion of the td and not from the medial septal nucleus, (2) the td contains cholinergic cell bodies which project widely to the cortex and hippocampus. It is suggested that these cholinergic projections have important influences on emotional behavior via connections with the cortex and limbic system.

Acetylcholine↗
PubMed1983

Sex differences in specific proteins in the preoptic medial nucleus of the rat hypothalamus.

Using two-dimensional gel electrophoresis and a highly sensitive silver stain, specific proteins in adult male and female rat brain were examined. Based on previous studies, the preoptic medial nucleus (POM) of the hypothalamus served as the area of interest, with the parietal cortex acting as control. A significant difference between the sexes was found in the concentration of two proteins in the POM, a difference which was not found in the parietal cortex.

Animals↗
PubMed1983

Mapping and quantitation of proteins from discrete nuclei and other areas of the rat brain by two-dimensional gel electrophoresis.

A map of the location and relative concentration of a number of different proteins present in 25 distinct neuroanatomical regions of the male rat brain has been established utilizing two-dimensional polyacrylamide gel electrophoresis. The regions examined include cortical areas as well as nuclei from the hypothalamus, amygdala, thalamus, forebrain, and hindbrain. Tissue samples were obtained from each region of interest by microdissection. Proteins within these samples were first separated by charge using the technique of isoelectric focusing. In the second dimension, proteins were separated by mass on polyacrylamide slab gels containing sodium dodecyl sulfate. Proteins were visualized using a highly sensitive silver stain and quantitated by computerized scanning densitometry. The results demonstrate that all proteins examined varied somewhat in concentration among the different brain regions. The majority (53%) of polypeptides selected for quantitation were found to vary less than 4-fold in concentration between the neuroanatomical areas with the lowest and highest detected amounts. In contrast, approximately 10% of the proteins examined varied widely in the quantity measured in each brain region, with concentration values ranging more than 10-fold between the regions with the lowest and highest detected amounts. This atlas is a first attempt at systematically classifying the mass, charge, and relative concentration of proteins present in a variety of regions of the rat brain. The system presented here will serve as a basis for future studies in this area.

Animals↗