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Biomedical subjects

I Barker

Publications and source records attributed to I Barker.

At least 19 recordsLinked to original sources
PubMed2001

Detection of different strains of Potato virus Y and their mixed infections using competitive fluorescent RT-PCR.

A competitive fluorescent RT-PCR assay (CF RT-PCR) was developed for the rapid and reliable detection and discrimination of the two most common strains of Potato virus Y (PVY) found in potato (necrotic and ordinary). The assay incorporates two strain specific primers labelled with fluorescent labels, used in conjunction with a universal PVY primer. The strain specific primers compete for the same annealing site which further increases specificity. Discrimination is conferred by the fluorescent labels; green PCR products for PVY(O) and red for PVY(N), whilst mixed infections are detected as orange PCR products without the need for staining agarose gels. The assay can be scaled up for the processing of 96 samples simultaneously, with the detection of PCR products directly using a fluorescent microtitre plate reader. The assay successfully discriminated between 20 isolates of PVY tested, and could be used for the direct detection of PVY in potato tubers.

Antibodies, Viral↗
PubMed1998

Strain specific recombinant antibodies to potato virus Y potyvirus.

Single chain Fv antibody fragments have been selected from a synthetic phage-antibody library following three and four rounds of affinity selection with purified potato virus Y, common strain (PVY(O)). The selected fragments were highly specific for PVY and detected seven out of nine isolates of PVY(O) whilst failing to detect three isolates of PVY(N) and 12 isolates of PVY(NTN). Nucleotide sequence of the scFv genes showed the variable heavy fragments belonged to the human VH4 family, whilst the variable light fragments belonged to the Vlambda1 family. The fragments were used in ELISA to detect virus at concentrations of 50 ng/ml in plant sap and in comparisons with commercially available PVY monoclonal antibodies were shown to have similar limits of detection. This is the first report of the selection of a scFv specific for a member of the potyviridae, and its use in detecting and differentiating strains of PVY in infected plant sap. The results highlight the potential of the technology for the selection of strain specific antibodies with an avidity equivalent to traditional monoclonal antibodies raised against viral pathogens and their use for viral diagnosis.

Amino Acid Sequence↗
PubMed1998

Anaesthetic management of a child with Burkitt's lymphoma of the larynx.

An eight-year-old boy with a Burkitt's lymphoma of the upper airway is described. The use of sevoflurane for induction of anaesthesia in patients with airway obstruction is discussed. The logistical problems of upper airway surgery and anaesthesia in this type of patient are considered.

Anesthesia, Inhalation↗
PubMed1998

Anaesthetic training programmes in the UK: the role of the programme director.

Schools of anaesthesia provide anaesthetic training in the UK. Each school has at least one programme director undertaking some or all of the management duties. Most programme directors appears to be unresourced volunteers whose roles have developed in response to local requirements. A postal questionnaire was sent to all anaesthetic training programme directors in the UK, asking about their role. Respondents had a wide variation in duties and responsibilities towards anaesthetic training schemes. Few had terms of reference, clear lines of responsibility, remuneration or resources to undertake the role.

Anesthesiology↗
PubMed1997

Propofol infusion vs thiopentone/isoflurane anaesthesia for prominent ear correction in children.

Postoperative nausea and vomiting (PONV) frequently follows prominent ear correction under general anaesthesia in children. In a prospective, single-blind study, we compared the incidence of PONV after propofol infusion anaesthesia with that following thiopentone induction and isoflurane maintenance in 30 children aged from four to 14 years randomly allocated to one of two groups. All the children were mechanically ventilated. Anaesthesia was supplemented in both groups with nitrous oxide and infiltration of the ears using a mixture of bupivacaine, adrenaline, and hyaluronidase. One child receiving propofol (group P) complained of nausea, compared with eight receiving thiopentone/ isoflurane, (group T) (P = 0.005), while three children in group P and ten in group T vomited before hospital discharge, (P = 0.01). Eight children in group P were considered to be fit for discharge on the day of surgery as against four in group T, (not significant). Only four out of twelve children receiving opioid analgesia vomited.

Adolescent↗
PubMed1997

A comparison of thiopentone-isoflurane anaesthesia vs propofol infusion in children having repeat minor haematological procedures.

We have performed a randomized, cross over study in 22 children suffering from acute leukaemia, who underwent repeated anaesthesia for bone marrow aspiration and lumbar puncture. For their first anaesthetic, the children (aged 3-10 years old) received, either a thiopentone/isoflurane anaesthetic or intravenous propofol, both supplemented with nitrous oxide. On a second occasion they received the alternative technique. Of those children receiving thiopentone/isoflurane, 32% had significant coughing during anaesthesia, two progressing to laryngospasm requiring 100% oxygen. None of the patients receiving propofol had a respiratory disturbance (P = 0.016). 68% of the children preferred the propofol anaesthetic. Only one child in the thiopentone/isoflurane group preferred this technique. Twenty-seven per cent had no preference. There was no significant difference in length of anaesthetic time (P = 0.07) or the time taken for recovery (P = 0.17) between the two groups. There was a large individual variation in propofol requirements and movement was common during stimulation of patients in this group, though this did not adversely affect the surgical procedure.

Acute Disease↗
PubMed1996

Improved detection of barley yellow dwarf virus in single aphids using RT-PCR.

The detection of a British isolate of barley yellow dwarf virus (BYDV-G, PAV-like) from individual vector aphids, using a combined assay of reverse transcription and polymerase chain reaction (RT-PCR) is reported. The method makes use of a multiplex format, including internal control primers directed at conserved regions of insect actin. The actin primers serve as controls for each stage of the method and are suitable for use in a range of invertebrate species. Detection of BYDV in vector aphids for use in forecasting systems is at present carried out using an enzyme-amplified ELISA system. In direct comparisons with the amplified ELISA, RT-PCR shows an increase in sensitivity detecting 11 fg of purified virus. Detection of virus in ELISA-negative aphids by RT-PCR was also demonstrated, and its potential as a routine diagnostic tool for virus detection in aphids is discussed.

Animals↗
PubMed1996

An improved method for the detection of Tospoviruses using the polymerase chain reaction.

A reverse transcription-polymerase chain reaction (RT-PCR)-based assay for the detection of tomato spotted wilt virus (TSWV) has been improved and extended to enable the detection of additional Tospoviruses. In addition to TSWV-specific primers, two further pairs of primers have been designed, one pair which specifically detects impatiens necrotic spot virus (INSV) and another which detects all Tospoviruses tested, including TSWV, INSV, tomato chlorotic spot virus and groundnut ringspot virus. An improved, rapid RNA extraction method is also described.

Base Sequence↗