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Biomedical subjects

M Carrington

Publications and source records attributed to M Carrington.

133 records · Page 8Linked to original sources
PubMed1987

The structure and transcription of an element interspersed between tandem arrays of mini-exon donor RNA genes in Trypanosoma brucei.

Messenger RNAs in Trypanosoma brucei brucei have the same 35 bases at the 5' end. These 35 bases are not encoded contiguously in the genome, but are donated from a 140 base RNA (the mini-exon donor RNA). The mini-exon donor RNA (medRNA) is encoded by 1.35 kbp genes that occur in tandem repeats. A DNA element that is associated with mini-exon donor RNA medRNA genes has been identified and characterised by restriction enzyme mapping and partial sequencing. This element (the medRNA gene associated element: MAE) varies in length between 5.5 and 7 kbp. There are between 20 and 40 copies of the element per haploid genome. In clones of genomic DNA MAEs occurred between two medRNA gene arrays and on both sides of a medRNA gene array. The MAEs were always in the same orientation with respect to the medRNA genes. It is proposed that in the genome MAEs are interspersed between tandem arrays of medRNA genes. The transcription of the element has been investigated. Low levels of a 70-80 base transcript derived from a small part of MAE were detected in steady state RNA. Nuclear run off transcript studies indicated that MAEs were transcribed at high levels and that they possibly contain at least one start and stop of transcription.

Animals↗
PubMedDate not supplied

Expression of a polypeptide containing a dipeptide repeat is confined to the insect stage of Trypanosoma brucei.

The protozoan parasite Trypanosoma brucei is transmitted between mammalian hosts by the tsetse fly (Glossina spp.). Trypanosomes ingested by the fly undergo a number of changes in the insect midgut during differentiation to procyclic forms. These include the loss of the variant specific glycoprotein (VSG) coat and the appearance of a common set of procyclic surface antigens. In order to investigate genes other than VSG genes which are expressed only at certain stages of the life cycle, the first cDNA specific to procyclic culture form trypanosomes (equivalent to the stage found in the insect midgut) has been characterized. The encoded polypeptide shows several characteristics of membrane proteins, but its most striking feature is the presence of a repetitive amino-acid sequence in which there are 22 tandem repeats of the dipeptide-Glu-Pro-. Related genes are also found in other trypanosome species and in leishmania. This gene shows many similarities to a number of surface antigen genes described in malaria and, more recently, Trypanosoma cruzi. This is the first example of a repetitive sequence in a parasite protein which is present only in the insect vector, and which therefore cannot be implicated in the mammalian host immune response.

Amino Acid Sequence↗
PubMedDate not supplied

Peripheral i.v. cannula dressings: advantages and disadvantages.

There are many peripheral intravenous cannula dressings being used throughout the country. This article is a review of these dressings and looks at those used in the authors' trust as well as other products on the market. The article gives an overview of the advantages and disadvantages of the different dressings, including costs, that allow medical and nursing staff to make an informed choice about the type of dressing they use. The authors felt, given all the evidence, the traditional method of using gauze, tape or mefix was no longer acceptable practice.

Bandages↗
PubMedDate not supplied

A practical guide to venepuncture and management of complications.

For years many nurses have felt that if they had the ability to perform skills such as venepuncture they would be able to provide a more holistic and efficient service. The culture in which nurses and doctors have traditionally worked has often made it difficult for nurses to become competent at such skills. However, the boundaries of medical and nursing roles have started to change and a culture of shared roles is emerging which has many benefits for patients, medical staff and nursing staff. This article provides a practical guide to venepuncture. It highlights the structure of a vein and the veins that are suitable for venepuncture. It also addresses the prevention and management of potential complications.

Catheterization, Peripheral↗