Why CEOs fail.
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Administrative Personnel↗
Biomedical subjects
G Colvin
Publications and source records attributed to G Colvin.
Use of the 'Analmatic clinical system' in the microbiological assay of vitamin B 12 and folic acid in serum.
The routine estimation of large numbers of serum folic acid and vitamin B(12) levels using the Baird and Tatlock(1) Analmatic clinical system is described and the method evaluated.Precision, accuracy, and carryover are shown to be at acceptable levels, and the advantages and disadvantages of the use of the system are discussed. It is considered that with some modifications the Analmatic system offers a reliable and labour-saving method of carrying out considerable numbers of routine microbiological assays.
Autoanalysis↗
Pharmacology and toxicology of europium chloride.
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Animals↗
Physical and physiological plasticity of hematopoietic stem cells.
Stem cells from a variety of tissues have recently been shown to be capable of differentiating into cells characteristic of a separate tissue, apparently in response to microenvironmental signals. This is hierarchical plasticity. We have shown that both human and murine neurosphere cells with potential for differentiating into neurons, oligodendrocytes, and astrocytes can produce hematopoietic stem cells when engrafted into fetal sheep or murine day 3.5 blastocysts, respectively. We have also demonstrated an alternative form of stem cell plasticity: functional plasticity at different points in cell cycle transit and at different phases of a circadian rhythm. We have shown that long-term engraftment varies reversibly as primitive murine stem cells (lineage-negative rhodamine(low) Hoechst(low)) transit the cell cycle under stimulation by interleukin-3 (IL-3), IL-6, IL-11, and steel factor, with engraftment being defective in late S/early G2. Engraftment also varies markedly with circadian time. Presumptive mechanisms for these phenotypic shifts include alteration in adhesion protein expression with consequent changes in marrow homing. Most recently, we have also demonstrated that stem cell differentiation varies markedly with cell cycle transit. There are other features of the hematopoietic stem cell which suggest that it is a highly plastic cell with the ability to rapidly change its membrane phenotype, while exhibiting extraordinary directed motility. These data suggest that cell cycle and circadian plasticity should be considered additional major features of the hematopoietic stem cell phenotype.
Animals↗