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Biomedical subjects

K Porter

Publications and source records attributed to K Porter.

At least 73 records · Page 4Linked to original sources
PubMed1986

The interactive effects of alcohol and mood on dual-task performance.

The interactive effects of mood induction and alcohol consumption were examined in a combined visual digit detection and tracking task. Although tracking ability was independently sensitive to both time on task and alcohol, no interaction between alcohol and mood was observed. However, correct reaction times on the digit detection task were sensitive to such interactive effects. Those individuals who both consumed alcohol and watched a descriptive film performed worse on this part of the task throughout the session compared to those who watched a humorous film and did not take alcohol. Correlational analyses between performance on the tracking and digit detection tasks do not necessarily support the contention that alcohol may serve to disrupt the operation of a timesharing process.

Adolescent↗
PubMed1986

Bier's block--an improved technique.

A simple modification to the method of regional anaesthesia known as Bier's block is presented. This was applied to patients with Colles' fractures. In a controlled trial the technique produced anaesthesia more quickly than the other method.

Anesthesia, Conduction↗
PubMed1984

High-voltage electron microscopy of human diploid fibroblasts during ageing in vitro. Morphometric analysis of mitochondria.

Since recent studies have suggested a diminished mitochondrial functional capacity in late-passage ('old') compared to early-passage ('young') normal fibroblasts and fibroblasts from the Hutchinson-Gilford (progeria) syndrome of premature ageing, we analysed whole-cell preparations on the high voltage electron microscope to look for mitochondrial and related defects. All strains examined showed considerable heterogeneity in cell size and intracellular morphology. Mitochondria were readily seen in all cells, predominantly as long slender rods with frequent branching, but occasional circular and saccular forms were also evident. Various parameters of mitochondrial mass including mean number, weight, and total length of mitochondria per cell weight tended to increase in old and progeria cells, but only the former attained statistical significance due to the heterogeneity and consequent variance. A significant finding was the decreased width of mitochondria in old and progeria cells. Cystic blebs were evident in mitochondria of some cells with an apparent increase in old and progeria fibroblasts. These blebs appeared to be due to weakening of the inner membrane, allowing dilatation of the outer membrane which otherwise appeared intact. The number of osmiophilic inclusions per cell weight, particularly lipofuscin granules and autophagic vacuoles, was significantly increased in old and progeria cells. In conclusion, despite some morphological changes, mitochondria of old and progeria cells maintain a structurally and bioenergetically adequate mass compatible with continued cellular viability.

Aging↗
PubMed1979

Uptake of radioactive calcium by hard tissue cells.

45Ca was injected into prenatal mice to study the calcium uptake by tooth germ cells. Both dental papillae, containing the odontoblasts, and the enamel organs were found to actively metabolized the labeled calcium. The maximum specific radioactivity occurred at 15 minutes after injection. The subcellular organelles (e.g. mitochondria) of the papillae were more active in metabolizing the labeled calcium whereas a large portion of the radioactivity of the enamel organ was found in a fraction containing the precalcified material. In fetal tooth germs, the rate of incorporation of labeled calcium into the precalcified material was slower than in the postnatal tooth germs since a large portion of the radioactivity remained in the soluble fraction.

Animals↗
PubMed1977

Chemical synthesis of the hexanucleotide d(A-C-C-A-G-C) required to isolate fibroin mRNA on an affinity column.

The synthesis of the hexanucleotide d)A-C-C-A-G-C), complementary to the 2 major triplets of fibroin mRNA, using the phosphotriester methodology is described. The protected dinucleotides ((MeO)2Tr)dbzA.anC, ((MeO)2Tr)danC.bzA and ((meO)2Tr)dacG.anC were synthesized; the latter two were detritylated and joined in stepwize fashion to the 1st to form the protected hexanucleotide ((MeO)2Tr)dbzA.anC.anC.bzA.acG.anC. The latter was deblocked with NH3 and acid to form the hexanucleotide d(A-C-C-A-G-C). In view of the ability of a prototype affinity column, oligo dC-cellulose, to isolate fibroin mRNA, prospects appear excellent for the d(A-C-C-A-G-C)-cellulose affinity column isolation of fibroin mRNA.

Chromatography, Affinity↗