Effects of type of social reinforcement on the intelligence test performance of lower-class black children.
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Biomedical subjects
Publications and source records attributed to J Taylor.
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RNA extracted from Tilligerry virus, a member of the Eubenangee group of orbiviruses, separated into ten segments after electrophoresis in acrylamide gels. The molecular weights of most segments differed from the corresponding segments of Eubenangee virus.
Temperature-sensitive mutants of the related orbiviruses, Wallal and Mudjinbarry, recombine with high frequency when grown in pairs in cell culture. The genome of each virus consists of discrete segments of double-stranded RNA and high frequency recombination suggests that reassortment of genome segments occurs rather than classical recombination. Electrophoresis in acrylamide gels of RNA extracted from the progeny of a cross between Wallal ts 101 and Mudjinbarry ts 3 mutants, revealed that three plaque isolates of 60 tested differed in RNA pattern from each of the parent viruses and from each other. Further analysis of the electrophoretic profiles suggested that the isolates were recombinants with RNA segments derived from each of the parent viruses.
In a case of dihydrolipoyl dehydrogenase deficiency, there was not only an elevation of lactate and alpha-ketoglutarate but also of branched chain amino acids. The levels of branched-chain amino acids varied from the normal range to three times the upper limit of normal during the patient's lifetime, and alloisoleucine was detectable at all times. Examination of postmortem tissues revealed that the activity of branched-chain keto acid dehydrogenases was between zero and 10% of that in control tissues. It is suggested that the multiple defects seen in oxidative decarboxylation in this patient is the consequence of a single genetic deletion of an enzyme common to pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, and branched chain keto acid dehydrogenases.
The activities of five mitochondrial enzymes tested in liver from patients with Reye's syndrome were measured. Citrate synthase, glutamic dehydrogenase, succinic dehydrogenase, pyruvate carboxylase, and pyruvate dehydrogenase were all outside of the range shown by control samples and well below them in activity. The activity of two extramitochondrial enzymes, glucose-6-phosphatase, which is a microsomal enzyme, and fructose-1,6-diphosphatase, which is a soluble enzyme, were in the normal range in samples from Reye's syndrome patients. In both muscle and brain the activities of the mitochondrial enzyme, citrate synthase, glutamic dehydrogenase, and succinic dehydrogenase were all within the control range. Pyruvate dehydrogenase was found to be normal in muscle from these patients.
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Exacerbation of focal sclerosing glomerulopathy (FSGN) during pregnancy was noted in the three patients. All had antecedent asymptomatic proteinuria. Toxemia developed in two of the women during pregnancy and progressed rapidly to renal failure. Severe nephrotic syndrome developed in one patient with pregnancy and remitted after delivery. These cases suggest a deleterious effect of pregnancy on the course of FSGN and indicate the necessity for doing renal biopsy in women of childbearing age with asymptomatic fixed proteinuria or nephrotic syndrome so that those patients with FSGN can be properly counseled about future pregnancies.
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28 children with chronic asthma (15 in Denver and 13 in London) completed a 12 wk double-blind trial of treatment with sodium cromoglycate (cromolyn sodium), theophylline, and a combination of both. The three regimens were administered, each for 4 wk, in random sequence as part of a collaborative investigation of the relative efficacy of the two antiasthmatic agents. Cromoglycate was administered by inhalation in standard doses of 20 mg q.i.d. Theophylline dosage was individualized with the assistance of serum-theophylline measurements and averaged 6 mg/kg/dose q.i.d. (range 3-8--8-5 mg/kg/dose). Peak expiratory-flow rates measured twice daily on all patients averaged 75% of that predicted during cromoglycate administration, 79% during theophylline, and 81% during the combined-drug regimen (P less than 0.05). Patients had an average of 59% of days free of symptoms while on cromoglycate and 71% of days symptom-free when on both the theophylline and the combination regimens (P less than 0.025). None of the 13 patients whose asthmatic symptoms were previously controlled with cromoglycate was unable to complete the 4 wk trial with theophylline alone; 1 patient whose symptoms had been previously controlled with theophylline twice developed severe asthmatic symptoms while receiving cromoglycate, and he had to be withdrawn from that study period. No significant differences in adverse effects of the medication were observed during the 12 wk trial.
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A fatty acid auxotroph of Candida albicans 6406, designated A' 44 and originally isolated as an oleic acid requiring strain, has been shown to be a delta9 desaturase mutant. Although lacking this step in fatty acid biosynthesis, it appears to retain the ability to desaturate monounsaturated fatty acids. The polyene sensitivity of the organism grown on different fatty acid supplements varied between 0-08 +/- 0-02 and 1-20 +/- 0-30 microgram amphotericin B methyl ester ml-1 for exponentially growing cells. In spite of this variation, the sterol composition remained fairly constant, the major differences lying in fatty acid composition. Stationary-phase cells were more resistant to amphotericin B methyl ester, although again this change was not associated with changes in sterol content. The organism was most resistant when grown in the presence of oleic or linoleic acid. Protoplasts derived from resistant organisms grown on these two fatty acids were also resistant, indicating that the structure of the cell wall was less important than that of the plasma membrane in determining polyene sensitivity under these conditions.
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A male child died at 7 months of age with progressive neurologic deterioration and persistent metabolic acidosis. Investigations during life showed this child to have elevated blood pyruvate, lactate, and alpha-ketoglutarate as well as elevation of branched chain amino acids and occasional hypoglycemia. Cofactor therapy using either thiamine-HCl (2 g/kg/24 hr) or thiamine tetrahydrofurfuryl disulfide had no measurable effect on the clinical or biochemical status of the patient. Tissue taken postmortem showed normal levels of key gluconeogenic enzymes but a deficiency in the activity of pyruvate dehydrogenase in all tissues tested (liver, brain, kidney, skeletal muscle, and heart). Examination of the individual activities of pyruvate dehydrogenase complex showed pyruvate decarboxylase (E1) to be normal in liver and other tissues. Dihydrolipoyl dehydrogenase (E3), on the other hand, was deficient in all tissues tested. alpha-Ketoglutarate dehydrogenase complex, which depends of E3 for its total activity, was also deficient in all tissues tested. The absence of this enzyme id discussed in relation to the clinical and biochemical status of the patient.
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