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J Steyaert

Publications and source records attributed to J Steyaert.

63 records · Page 4Linked to original sources
PubMed1989

Conformational stability and activity of ribonuclease T1 and mutants. Gln25----Lys, Glu58----Ala, and the double mutant.

Ribonuclease T1 (RNase T1) and mutants Gln25----Lys, Glu58----Ala, and the double mutant were prepared from a chemically synthesized gene, cloned and expressed in Escherichia coli. The wild-type RNase T1 prepared from the cloned gene was identical in every functional and physical property examined to RNase T1 prepared from Aspergillus oryzae. Urea and thermal unfolding experiments show that Gln25----Lys is 0.9 kcal/mol more stable and Glu58----Ala is 0.8 kcal/mol less stable than wild-type RNase T1. In the double mutant, these contributions cancel and the stability does not differ significantly from that of wild-type RNase T1. For the double mutant, the dependence of delta G on urea concentration is significantly greater than for wild-type RNase T1 or the single mutants. This suggests that the double mutant unfolds more completely in urea than the other proteins. The activity of Gln25----Lys is identical with that of wild-type RNase T1. The activities of Glu58----Ala and the double mutant are 7% of wild-type when GpC hydrolysis is measured (due to a 35-fold decrease in kcat), and 37% of wild-type when RNA hydrolysis is measured. Thus, Glu58 is important, but not essential to the activity of RNase T1.

Aspergillus oryzae↗
PubMed1983

Effects of test anxiety and sex of subject on neuropsychological test performance: Finger Tapping, Trail Making, Digit Span and Digit Symbol tests.

To determine the effects of anxiety and sex on various neuropsychological tests, 28 male and 28 female non-impaired, high and low test-anxious subjects were given the Finger Tapping, Trail Making (Forms A and B), Digit Span, and Digit Symbol tests. Sex significantly affected only the Finger Tapping Test; females made significantly fewer taps. High test-anxious subjects reported an increase in posttest state anxiety. However, test anxiety did not significantly affect performance.

Adolescent↗
PubMed1983

Three-drug chemotherapy combined with radiation therapy in small cell carcinoma of the lung.

In 43 cases of small cell carcinoma of the lung, a combined treatment has been initiated with three drugs (cyclophosphamide 750 mg/m2, adriamycin 50 mg/m2 and vincristine sulphate 1 or 2 mg total dosage), split-course-radiation therapy on the primary tumour (3500 rads) and prophylactic irradiation of the brain (2000 rads). The median survival of the 34 cases evaluable at day 50 attains 253 days. A more favourable evolution is observed for patients with a good response after therapy (median survival: 315 days) and for cases with limited disease (321 days) than for non-responders (median survival: 157 days) and for cases with extensive disease (median survival: 214 days). In spite of tumour site irradiation, prophylactic irradiation of CNS and chemotherapy, there were six local relapses, two CNS extensions and six metastatic relapses and only two autopsied cases without macroscopic evidence of relapse.

Adult↗
PubMedDate not supplied

Cognitive profile in adult, normal intelligent female fragile X carriers.

Here we present the results of the study of the cognitive profile of 11 adult, normally intelligent female fragile X [fra(X)] carriers. In all individuals 3 types of testing were performed: full scale Wechsler Adult Intelligence Scale, a set of neuropsychological tests and an arithmetic achievement test. All 11 subjects showed an average to above-average intelligence but 10 of 11 performed better on the performance than on the verbal subscale. Neuropsychological tests suggest a dysfunction of the reticulo-thalamic axis with deficiency on tests requiring visual memory and a pronounced deficiency of attention skills combined with an impulsive way of completing tests.

Adult↗