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T Cooper

Publications and source records attributed to T Cooper.

At least 109 records · Page 6Linked to original sources
PubMed1985

Different pattern of association of beta-endorphin and cortisol responses to dextroamphetamine in postmenopausal women and young men.

A negative correlation between plasma beta-endorphin and cortisol responses to 0.15 mg/kg dextroamphetamine i.v. was found in a group of seven normal postmenopausal women, while the responses of the two hormones were positively correlated in nine normal young men. These results suggest that even though the adrenocorticotropic hormone (ACTH)-cortisol and beta-endorphin are usually regulated by the same mechanism (both ACTH and beta-endorphin are derived from proopiocortin), there are situations in which these systems can be associated in a different pattern. The elucidation of these situations may contribute to the understanding of regulatory mechanisms of the two systems.

Adult↗
PubMed1984

Regional differences in the effect of pargyline on dopamine concentrations in the rat hypophysis.

Dopamine concentrations were estimated in different regions of the infundibular-pituitary system of the rat. The highest values were found in the pituitary stalk where they are comparable to the concentrations in the striatum, and higher than in the median eminence. In the anterior lobe the dopamine (DA) concentrations of the upper pole (10% of the lobe tissue) were 2-5 times higher than in the rest of the lobe. Anterior lobe DA was significantly higher in rats about 6 months old than in rats about 3 months old. After inhibition of MAO, the DA concentrations in the isolated neural lobe (NL) were more than doubled. In contrast there was no increase in the DA concentrations of the intermediate lobe, an observation which is in agreement with our previous finding that DA synthesis in the intermediate lobe after electrical stimulation of the pituitary stalk is much slower than in the neural lobe. Pargyline treatment caused an increase in the DA concentrations in the anterior lobe by about 150%. This rise (together with a DA increase in the stalk-infundibulum) may be related to the decrease in circulating prolactin which occurs in pargyline treated rats.

Aging↗
PubMed1984

cis-Dominant mutations which dramatically enhance DUR1,2 gene expression without affecting its normal regulation.

We have isolated three cis-dominant mutations which dramatically enhance DUR1 ,2 gene expression in Saccharomyces cerevisiae. The mutant phenotype, which is expressed both in haploid and MATa/MAT alpha diploid strains, does not appear to be an alteration of the normal control system for this gene because its expression remained fully inducible and sensitive to nitrogen catabolite repression. Instead, we found much higher levels of DUR1 ,2-specific RNA under both uninduced and induced conditions, i.e., the overproduction trait was superimposed on normal regulation of the gene. The mutations seemed to affect gene expression in a unidirectional manner or to be specific for DUR1 ,2 gene expression, because other genes in proximity to the mutations were not affected. We feel that these mutations may alter the chromatin structure in the vicinity of the DUR1 ,2 upstream control sequences or, alternatively, may be Ty insertions which no longer possess the ROAM characteristics reported by others and ourselves.

Base Sequence↗
PubMed1984

Hypothalamic-pituitary-adrenocortical function in geriatric depression: diagnostic and treatment implications.

Extensive work in the field has indicated a state-dependent hyperactivity of the hypothalamic-pituitary-adrenocortical (HYPAC) functions and unresponsiveness to dexamethasone suppression in at least 50% of patients suffering from endogenous depression. In this study, elderly outpatients, 60-85 years of age, suffering from major depressive illness according to research diagnostic criteria (RDC) were studied with the dexamethasone suppression test (DST). Careful diagnostic evaluation included RDC, the Newcastle index, and clinical interviews focusing on "endogenomorphic features." The great majority (83.3%) of patients diagnosed as endogenous depressives were nonsuppressors (abnormal DST) as compared to 16.7% nonsuppressors amongst nonendogenous patients. In addition, DST tended to normalize the clinical recovery. The research and clinical implications of our findings in this population are further discussed.

Aged↗
PubMed1982

Nonsense suppression in Schizosaccharomyces pombe: the S. pombe Sup3-e tRNASerUGA gene is active in S. cerevisiae.

The gene encoding the efficient UGA suppressor sup3-e of Schizosaccharomyces pombe was isolated by in vivo transformation of Saccharomyces cerevisiae UGA mutants with S. pombe sup3-e DNA. DNA from a clone bank of EcoRI fragments from a S. pombe sup3-e strain in the hybrid yeast vector YRp17 was used to transform the S. cerevisiae multiple auxotroph his4-260 leu2-2 trp1-1 to prototrophy. Transformants were isolated at a low frequency; they lost the ability to grow in minimal medium after passaging in non-selective media. This suggested the presence of the suppressor gene on the non-integrative plasmid. Plasmid DNA, isolated from the transformed S. cerevisiae cells and subsequently amplified in E. coli, transformed S. cerevisiae his4-260 leu2-2 trp1-1 to prototrophy. In this way a 2.4 kb S. pombe DNA fragment carrying the sup3-e gene was isolated. Sequence analysis revealed the presence of two tRNA coding regions separated by a spacer of only seven nucleotides. The sup3-e tRNASerUGA tRNA gene is followed by a sequence coding for the initiator tRNAMet. The transformation results demonstrate that the cloned S. pombe UGA suppressor is active in S. cerevisiae UGA mutant strains.

Ascomycota↗
PubMed1982

A candidate reference method for uric acid in serum. I. Optimization and evaluation.

We describe our optimization and evaluation of a candidate Reference Method for uric acid in serum. Reaction parameters were optimized for a manual, enzymic method for uric acid in which highly purified microbial uricase is used to quantitate uric acid by a differential ultraviolet procedure. We evaluated the method in terms of freedom from interferences, analytical recovery, precision, and comparison with five other uric acid methods. We conclude that (a) the candidate uric acid Reference Method exhibits the least interference; (b) all six methods exhibit satisfactory analytical recoveries and precision; and (c) results by all six methods agree well. As a result of this evaluation study, the manual ultraviolet uricase method for uric acid, with Tris as buffer, was chosen as the candidate Reference Method for uric acid.

Adult↗