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Biomedical subjects

P Johnstone

Publications and source records attributed to P Johnstone.

12 recordsLinked to original sources
PubMed1997

Rapid detection of rabies and rabies-related viruses by RT-PCR and enzyme-linked immunosorbent assay.

A rapid detection method for the six established genotypes of rabies and rabies-related viral RNA using RT-PCR-ELISA is described. The detection of digoxigenin-labelled amplified products is performed by solution hybridization to two specific, biotin-labelled, capture probes, which are complementary to the inner region of the amplification products. The capture probe and amplified product hybrid are then immobilised on a streptavidin-coated microtitre plate, bound products are detected by an anti-DIG Fab fragment conjugated to peroxidase, and colorimetric reaction automatically measured. This method was up to 100-fold more sensitive than Southern blot hybridization, detecting 0.00002 TCID50/ml of a genotype 1, classical rabies virus strain. The complete detection methodology from RT-PCR to PCR-ELISA detection could be completed within 10 h. Using this procedure, we were 100% successful in detecting 60 isolates from a representative selection of the six established genotypes from all over the world. This test is a useful additional tool for the detection of the rabies and rabies-related viruses, which is easy to perform, rapid and highly sensitive.

Animals↗
PubMed1997

Heminested PCR assay for detection of six genotypes of rabies and rabies-related viruses.

A heminested reverse transcriptase PCR (hnRT-PCR) protocol which is rapid and sensitive for the detection of rabies virus and rabies-related viruses is described. Sixty isolates from six of the seven genotypes of rabies and rabies-related viruses were screened successfully by hnRT-PCR and Southern blot hybridization. Of the 60 isolates, 93% (56 of 60) were positive by external PCR, while all isolates were detected by heminested PCR and Southern blot hybridization. We also report on a comparison of the sensitivity of the standard fluorescent-antibody test (FAT) for rabies antigen and that of hnRT-PCR for rabies viral RNA with degraded tissue infected with a genotype 1 virus. Results indicated that FAT failed to detect viral antigen in brain tissue that was incubated at 37 degrees C for greater than 72 h, while hnRT-PCR detected viral RNA in brain tissue that was incubated at 37 degrees C for 360 h.

Animals↗
PubMed1997

Rabies virus in the decomposed brain of an Ethiopian wolf detected by nested reverse transcription-polymerase chain reaction.

Approximately 75 individuals from a population of 111 Ethiopian wolves (Canis simensis) died or disappeared from the Bale Mountains National Park (Ethiopia) between 1988 and 1992 during two significant population declines. Confirmation of rabies virus in two carcasses was based on the fluorescent antibody test (FAT) and the mouse inoculation test (MIT). In an Ethiopian wolf brain previously designated rabies negative by both FAT and MIT, rabies virus was identified by nested reverse transcription-polymerase chain reaction (RT-PCR) and confirmed by Southern blot hybridization. These methods were successfully used on a highly decomposed brain sample which had been stored in 20% dimethyl sulfoxide. This test system allows early and sensitive detection to be undertaken to more effectively prevent spread of disease and thus protect surviving animals.

Animals↗
PubMed1996

Ten-year survey of British bats for the existence of rabies.

In 1985, a notable increase in the number of recorded cases of rabies in European bats was observed, indicating a possible spread of the rabies virus in these bats. Because of concern that the disease could be introduced into the United Kingdom by bats crossing from mainland Europe, a programme of screening dead bats for the presence of rabies and rabies-related viruses was initiated at the Rabies Research and Diagnostic Unit at the Central Veterinary Laboratory. Over a period of 10 years (January 1986 to December 1995), 1882 bats belonging to 23 species from all parts of England, Scotland and Wales have been screened for rabies antigen. All of these bats were found to be negative. Forty-one serotine bats (Eptesicus serotinus), the species of bat most commonly infected in Europe, were included in the total. Subsequent to this survey, in June 1996, a European bat lyssavirus 2 was isolated from a Daubenton's bat (Myotis daubentonii) in Newhaven, East Sussex. It is possible that this bat originated from mainland Europe but this cannot be established with certainty.

Animals↗
PubMed1996

Sequence variation in 5' termini of rubella virus genomes: changes affecting structure of the 5' proximal stem-loop.

Variation within a 523 nucleotide region proximal to the 5' terminus of seven rubella virus strains has been analysed. Compared to the Therien strain twenty sites of nucleotide variation have been identified, three of which are in the 5' untranslated region. Individual strains have between three and nine nucleotide differences, only three of which result in amino acid substitutions. TO-336 has a serine for threonine at amino acid (aa) 42 and CM arginine for histidine at aa 159. RA27/3 has arginine for lysine at aa 3 and serine for threonine at aa 42. Nucleotide differences which affect a stem-loop structure reported to be important for binding of host cell proteins have been identified.

Amino Acid Substitution↗
PubMed1995

Work in a developing country.

Some health professionals seek the exciting challenge of working for a time in a developing country. Uncertainties about taking this step, however, may have to be addressed. It is important to understand your reasons for wanting to work overseas-it is ill advised, for example, to go abroad just to escape job dissatisfaction in Britain. Skills needed for international aid work nowadays centre on low tech community based programmes, and enabling, facilitating, and managing skills are more important than clinical skills. Further training may be necessary. Careful planning both for the work abroad and for a return to work in Britain is advisable; full health insurance cover, for example, is important. Although working in a developing country is largely unrecognised as an asset to a professional career in Britain, attitudes are slowly changing. A spell overseas can be very relevant to a career plan and the NHS.

Developing Countries↗
PubMed1994

Potential use of nitroxides in radiation oncology.

The identification of radioprotectors is an important goal for those involved in radiation oncology and for those interested in the investigation of the mechanisms of radiation cytotoxicity. Recently, a new class of in vitro and in vivo radioprotectors, the nitroxides, has been discovered. The nitroxides are low-molecular-weight stable free radicals which are freely membrane permeable and which have been shown to act as superoxide dismutase mimics. Further investigation of these compounds has shown that a water-soluble nitroxide, Tempol, protects cultured Chinese hamster V79 cells from the cytotoxicity caused by superoxide, hydrogen peroxide, and t-butyl hydroperoxide. Tempol and five other water-soluble nitroxides have also been shown to protect V79 cells against radiation-induced cytotoxicity. Potential mechanisms of protection by the nitroxides include oxidation of reduced transition metals, superoxide dismutase-like activity, and scavenging of oxy- and carbon-based free radicals. In vivo studies reveal that Tempol protects C3H mice from the lethal effects of radiation with a dose causing 50% lethality within 30 days of 9.97 Gy and 7.84 Gy in Tempol-treated and saline-treated mice, respectively, and a dose modification factor of 1.3. The nitroxides represent a new class of non-thiol radioprotectors which may also have application as general antioxidants. Additional work is necessary to screen other nitroxides for in vivo radioprotection and toxicity as well as to fully evaluate the extent to which these compounds protect tumors.

Animals↗
PubMed1987

The parallel effects of a very low molecular weight heparin (CY222) on anti Xa activity and thyroid hormone levels in blood.

A very low molecular weight heparin fragment (CY222) was administered by subcutaneous injection to a group of normal volunteers. This drug caused increased anti Xa activity with peak levels being observed two hours after injection. This coincided with changes in thyroid hormone levels especially with a fall in red cell thyroxine levels. Larger doses of CY222 caused a fall in serum total thyroxine and triiodothyronine, a rise in free thyroxine and a fall in TSH levels. It was thought that these findings may be due to the production of a circulating inhibitor of cellular uptake of thyroxine and that this might be related to the elevated levels of serum free fatty acids produced by the heparin.

Factor X↗
PubMed1985

Follow-up of burned patients in the United Kingdom.

The nature of follow-up procedure practised by burn treatment units in the United Kingdom was investigated using a questionnaire sent to 30 units. Information from 23 units who replied indicated that all units consider that follow-up is essential and pressurized patients by a variety of means to attend. All units also recognized that medical, nursing and a variety of rehabilitation staff are required for follow-up care. There was a lesser involvement of social workers and a minimal involvement of psychiatric staff. All units obviously utilize a variety of clinics to follow patients after discharge from the burns unit. There appears to be no standard form of follow-up, units having made pragmatic arrangements to cover problems identified in clinical practice.

Burns↗
PubMed1979

Medieval arabic views on speech disorders: al-Razi (c. 865--925).

This paper discusses al-Razi's views on speech defects of lingual origin. It begins with a background sketch of the man, his times, and his major work, with its various translations. There follows translated extracts and analysis from his section on the causes and treatment of speech defects, seen in the light of the humoral theory of disease. Information is derived from the recently published Arabic version of Rzi's al-Hawi, which reveals that diagnosis was more advanced than is indicated in the Latin translations, which have been the principal source of reference in the West to date.

Adult↗