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Biomedical subjects

J M Robertson

Publications and source records attributed to J M Robertson.

At least 163 records · Page 9Linked to original sources
PubMed1980

Removal of contaminating polymorphonuclear leukocytes to prepare purified lymphocytes for cytotoxicity testing.

Human polymorphonuclear leukocytes (PMN) die, apparently nonspecifically, in the standard tissue typing assay. When the cell preparation contains more than 20% PMN, proper evaluation of the histocompatibility assay is difficult. PMN were noted to aggregate when normal rabbit serum was added as the complement source. Based on the latter observation, a simple technique was developed which reduces the PMN contamination in the suspension of test cells and returns high yields of lymphocytes. Removal of the PMN lowers the high background of dead cells and permits precise evaluation of the microcytotoxicity test results.

Absorption↗
PubMed1977

Interactions of yeast tRNAPhe with ribosomes from yeast and Escherichia coli. A fluorescence spectroscopic study.

The interaction of ethidium-labeled tRNAPhe from yeast with ribosomes from yeast and Escherichia coli was studied by stead-state measurements of fluorescence intensity and polarization. The ethidium label was covalently inserted into either the anticodon or the dihydrouridine loop of the tRNA. The codon-independent formation of a tRNA-ribosome complex led to only a moderate increase of the observed fluorescence polarization indicating a considerable internal mobility of the labeled parts of the tRNA molecule in the ribosome complex. When the ribosome complex was formed in the presence of poly(U), the probes both in the dihydrouridine loop and in the anticodon loop were strongly immobilized, the latter exhibiting a substantial increase in fluorescence intensity. A smaller intensity change was observed when E. coli ribosomes were used, although the extent of immobilization was found to be similar in this case. Competition experiments with non-labeled tRNAPhe showed that the labeled tRNAPheEtd was readily released from the complex with yeast ribosomes when poly(U) was absent, whereas in the presence of poly(U) it was bound practically irreversibly. The finding that the mobility of a probe in the dihydrouridine loop is affected by the codon-anticodon interaction on the ribosome suggests a conformational change of the ribosome-bound tRNA which may involve opening of the tertiary structure interactions between the dihydrouridine and the TpsiC loop.

Binding Sites↗
PubMed1977

Carotid-cavernous sinus fistula accompanying facial trauma.

The development of a carotid-cavernous sinus fistula is an uncommon complication of a maxillo-facial injury. A case report in which this developed within three days of injury is described, and the aetiology and incidence of the condition discussed.

Adolescent↗