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Biomedical subjects

J Barker

Publications and source records attributed to J Barker.

At least 163 records · Page 9Linked to original sources
PubMed1975

Hemoglobin synthesis in somatic cell hybrids: coexpression of mouse with human or chinese hamster globin genes in interspecific somatic cell hybrids of mouse erythroleukemia cells.

Somatic cell hybrids were derived by fusion of mouse erythroleukemia cells with fractionated human marrow enriched in erythroblasts, or with chinese hamster fetal liver erythroid cells. Such interspecific hybrid cells, when isolated in suspension culture, had retained nearly all the mouse chromosomes and had lost most of the human or chinese hamster chromosomes. However, two such hybrids (one human, the other hamster) studied 4-6 weeks after fusion, were found to contain several non-mouse chromosomes. RNA extracted from the human marrow x erythroleukemia hybrid annealed equally to both human and mouse globin complementary DNA, indicating that coexpression of the globin genes of each species had occurred in the hybrid cells. Mouse and human mRNA were found to accumulate only after incubation of the cells in 2% dimethylsulfoxide. The chinese hamster x erythroleukemia hybrid appeared to contain a double complement of mouse chromosomes in addition to several chinese hamster chromosomes. After 7 days of incubation in 2% dimethylsulfoxide, [3H]leucine was incorporated into chinese hamster beta-globin and the mouse globin chains. Thus, globin genes from differentiated cells, when introduced into spontaneously proliferating erythroleukemia cells, may be expressed after exposure of the resulting hybrid cells to an agent capable of inducing hemoglobin synthesis in the erythroleukemia cell.

Animals↗
PubMed1975

Observations on the growth and movement of Acinetobacter on semi-solid media.

The growth of 29 strains of Acinetobacter spp. on semi-solid media was studied; 19 showed surface swarming and 14 produced channels ("ditches") in the agar that do not seem to have been described previously. An attempt was made to define the cultural and physical conditions for the demonstration of these phenomena. Possible taxonomic implications are discussed.

Acinetobacter↗
PubMed1974

Cerebral blood flow, internal carotid artery pressure, and the EEG as a guide to the safety of carotid ligation.

Twenty patients with aneurysms of the internal carotid artery underwent temporary clamping, in turn, of the internal and then the common carotid artery. Cerebral blood flow, internal carotid artery pressure, and the EEG were recorded to assess the probability of cerebral ischaemia after permanent ligation. With this method of monitoring the cerebral circulation, 17 of the 20 patients had a permanent carotid ligation without neurological deficit; in the other three ligation was contraindicated. Although a correlation was observed between the reduction of cerebral blood flow and the fall in internal carotid artery pressure caused by temporary clamping (P<0·01), the scatter of data was too wide to predict cerebral blood flow from the change in carotid artery pressure. Similarly, EEG slowing was usually associated with low cerebral blood flow but exceptions occurred. Ligation was safe when, during temporary clamping, cerebral blood flow exceeded 40 ml/100 g/min, but was deemed unsafe when flow was less than 20 ml/100 g/min. In the range 20-40 ml/100 g/min, consideration of the internal carotid artery pressure permitted more patients to be safely ligated than if the decision had rested on changes in cerebral blood flow alone.

Adolescent↗