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Biomedical subjects

R T Anderson

Publications and source records attributed to R T Anderson.

52 records · Page 3Linked to original sources
PubMed1979

In vivo inhibitors of Escherichia coli phenylalanyl-tRNA synthetase.

N-Benzyl-D-amphetamine is a potent in vitro and in vivo inhibitor of phenylalanyl-tRNA synthetase of Escherichia coli. The concentration of this inhibitor necessary for the in vivo inhibition is approximately 100-fold greater than that necessary for inhibition of the purified enzyme. Treatment of rel+ strains of E. coli with the inhibitor results in a decreased percentage of tRNA Phe which is charged, guanosine tetraphosphate formation, cessation of RNA synthesis, and growth arrest. Evidence is presented which demonstrates that the primary and perhaps sole mode of action of N-benzyl-D-amphetamine is inhibition of phenylalanyl-tRNA synthetase.

Amino Acyl-tRNA Synthetases↗
PubMed1976

Phenylalanyl transfer ribonucleic acid synthetase from Escherichia coli B. Potent inhibition by analogues of N-benzyl-2-phenylethylamine.

A potent new class of inhibitors of phenylalanyl-tRNA synthetase from Escherichia coli B is described. N-Benzyl-2-phenylethylamine is a competitive inhibitor with respect to L-phenylalanine and appears to possess the structural features required for near-optimal binding. Hydrophobic substituents at the ortho position of either ring appear to be well tolerated, but substituents on both rings lead to large losses in binding. Poor noncompetitive inhibitors resllt from alkylation of the secondary nitrogen, further separation of the N-benzyl group from the nitrogen, or alkylation at the alpha position of the N-benzyl moiety. In contrast, placement of a methyl group at the 1 position of the 2-phenylethylamine moiety to give N-benzyl-D-amphetamine results in the most potent inhibitor yet described for this enzyme.

Amino Acyl-tRNA Synthetases↗
PubMed1976

Transcatheter therapeutic embolization in the management of massive upper gastrointestinal bleeding.

Two methods of controlling life-threatening hemorrhage are infusion of vasospastic agents and embolization of the bleeding vessel. Gelfoam powder, Gelfoam sponge, and isobutyl cyanoacrylate have been used to control severe arterial and variceal hemorrhage from the upper gastrointestinal tract. The authors summarize their results and discuss gastric necrosis, a serious complication.

Adult↗
PubMedDate not supplied

Distinguishing between phonological difference and disorder in children who speak African-American Vernacular English: an experimental testing instrument.

This study was conducted to evaluate the effectiveness of an experimental articulation testing instrument for differentiating child speakers of African-American Vernacular English (AAVE) with atypical and typical phonologies. Twenty-six AAVE-speaking children between the ages of 5:0 and 6:6 participated in the study. Based on their phonological skills in AAVE, the children were divided into two groups: typical and atypical. The experimental procedure was administered to each child and group performance on the instrument was contrasted. Significant group differences were observed thus suggesting that the experimental testing instrument can differentiate between AAVE-speaking children with typical and atypical phonological development between the ages tested. Observed error patterns are described and suggestions for further research are discussed.

Black or African American↗
PubMedDate not supplied

Learning an invented inflectional morpheme in Spanish by children with typical language skills and with specific language impairment (SLI).

Cross-linguistic research on SLI has suggested that how the disorder is manifested depends on the ambient language. For example, research on Italian indicates that SLI children do not present difficulties with verb inflection, when compared with MLU-matched peers. This pattern contrasts with what has been reported for English-speaking children. The present investigation sought to examine SLI children's use of inflectional morphology through a language teaching task similar to that used by Connell (1987) and Connell and Stone (1992). To address cross-linguistic differences, children were speakers of a language similar to Italian in its verb agreement paradigm. Sixteen Puerto Rican Spanish-speaking with SLI and 16 age-matched controls were taught a subject-verb agreement suffix that established the subject's gender. Half the children in each group were taught the new form via imitation. The rest of the participants were trained via a modeling procedure. Both comprehension and production of the target form were assessed. Results indicated significant differences across the SLI and typical groups for both comprehension and production of the inflectional morpheme, regardless of instructional strategy. These findings contradict what has been observed in previous studies on teaching an invented rule to children with SLI. They also suggest that inflectional morphology may be problematic even for children who are learning a morphologically rich language. The explanatory power of the process account and the linguistic account of SLI are explored as these pertain to the present findings, and suggestions for further research are discussed.

Case-Control Studies↗