Search PubMed⌕ Search

Biomedical subjects

P Schofield

Publications and source records attributed to P Schofield.

At least 109 records · Page 6Linked to original sources
PubMed1977

Reflexes in cat ankle muscles after landing from falls.

1. Electrical activity and length of ankle muscles were recorded by telemetry during free fall and landing in cats. 2. After foot contact, there was a delay in onset of stretch of ankle extensors of between 8 and 11 ms. High-speed cinematography showed the delay to be associated with rapid initial dorsiflexion of the toes. 3. Electromyograms (e.m.g.) from lateral gastrocnemius increased in amplitude prior to landing. An early depression of lateral gastrocnemius e.m.g. commenced at 8 ms after foot contact, and was followed by a large peak of activity commencing some 8 ms after the first increase in lateral gastrocnemius length. 4. Local anaesthesia of the plantar cushion did not alter this pattern of response. 5. The early inhibition of lateral gastrocnemius was attributed to the action on lateral gastrocnemius motoneurones of non-cutaneous afferents responding to the initial toe dorsiflexion. Additional autogenetic inhibition may also have contributed. 6. The subsequent peak of e.m.g. was at a latenty consistent with a rapid stretch reflex, and occurred soon enough for the resulting active tension to contribute significantly to the extensor force during body deceleration.

Animals↗
PubMed1976

Cryosurgical haemorrhoidectomy.

One hundred consecutive cases of haemorrhoids were treated by cryosurgery. The cryoprobe used is a convenient and simple instrument and gave a satisfactory result in 94 of the patients. The technique and complications are described. The patients were treated as outpatients, usually without anaesthesia.

Adult↗
PubMed1969

Spin-labeled transfer RNA.

The alpha-amino group of valyl-tRNA has been combined chemically with a nitroxide spin label through an amide linkage. This spin-labeled aminoacyl-tRNA has an electron paramagnetic resonance spectrum which reflects the mobility of the aminoacyl end of the tRNA molecule. The rate of tumbling of the spin label has been measured as a function of temperature and ionic strength. An abrupt transition in the nature of the motion occurs at a temperature which is sensitive to the ionic strength of the medium. This change in behavior of the aminoacylated spin label occurs at the same temperature as the midpoint of the optical density melting curves in dilute salt solutions. However, when denaturing agents such as dimethylsulfoxide or urea are added to the solution, the spin melting temperature is lower than the melting temperature as measured by the change in optical density. This suggests that under these conditions the local region of the aminoacyl end of the molecule denatures before the rest of the molecule is disrupted.

Carbon Isotopes↗
PubMed1969

Some observations on the near ultraviolet circular dichroism of tRNA from E. coli.

The circular dichroism arising from 4-thiouridine residues in E. coli transfer RNA has been studied under conditions in which the secondary and tertiary structure of the macromolecule is either intact or totally disrupted. Studies on both unfractionated tRNA and on highly purified species of methionine-, valine-, and lysine-specific tRNA suggest that the circular dichroism of the 4-thiouridine residue is highly sensitive to its local environment in the macro-molecule and reveal interesting differences between these purified species. A new chromophore, resembling 4-thiouridine in some respects but showing distinctive chemical and optical properties, has been detected. The implications of these results on model-building studies of tRNA are discussed.

Escherichia coli↗
PubMedDate not supplied

A mouse homoeo box gene is expressed during embryogenesis and in adult kidney.

The homoeo box sequence of Drosophila is an element located in several genes that regulate segmentation and segment identity; it has homologues in the genomes of vertebrate species and a number of homoeo box-containing recombinant DNA clones have been isolated from Xenopus, man and mouse. In the present study we have isolated from a library of murine DNA a recombinant lambda clone (H24.1) which contains a sequence closely homologous to the homoeo box within the Drosophila Antennapedia (Antp) gene. The protein sequence of the homoeo domain is identical to that encoded by Hu-1, one of a the pair of closely linked homoeo boxes in the human genome. We have used a sensitive RNase protection assay to examine transcription of the H24.1 gene during mouse development, and in adult tissues. We report that the gene is transcribed from as early as 7.5 days post coitum (p.c.), with maximum expression at days 11.5 and 12.5 p.c. The transcript is enriched in embryonic spinal cord and brain at day 12.5 p.c., and in adult kidney.

Age Factors↗
PubMedDate not supplied

Introducing a professional doctorate in nursing and midwifery.

The convergence of a number of factors has led to the emergence of what has come to be known as the 'professional doctorate'. This new doctoral education diverges from the model of research doctorates that have historically predominated for more than a century. The background to these changes and the impetus for the development of this relatively new approach to doctoral preparation is outlined in this article. The infancy of the professional doctorate means little empirical data exist about their operation or their success. In this light, the development of an evaluative framework is described in relation to the implementation of a new professional doctorate for nurses and midwives that has been introduced at the University of Sheffield.

Curriculum↗