Real-time bacterial detection with an intracellular ROS sensing platform.

Reactive oxygen species are highly reactive molecules that as well as being ubiquitously expressed throughout the body, are also known to be involved in many diseases and disorders including bacterial infection. Current technology has limited success in the accurate detection and identification of specific reactive oxygen species. To combat this, we have developed an electrochemical biosensor that is constructed from single walled carbon nanotubes that have been immobilised on an indium tin oxide surface functionalised with osmium-based compound. This sensor was integrated within mouse macrophage cells (RAW 264.7) with multiple serotypes of bacteria used to initiate an immune response. Intracellular hydrogen peroxide was then measured in response to the interaction of the lipopolysaccharides, present on the outer wall of Gram-negative bacteria, with the Toll-like Receptor 4. Additional controls of n-acetylcysteine and sodium pyruvate were implemented to prove the specificity of the sensor towards hydrogen peroxide. The sensors were found to have a lower limit of detection of 368 nM hydrogen peroxide. An increase in intracellular hydrogen peroxide was detected within 3 seconds of interaction of the bacteria with the macrophage cells. This low limit of detection combined with the rapid response of the sensor resulted in the unprecedented detection of hydrogen peroxide on a temporal level not previously seen in response to a bacterial threat. From the three serotypes of Gram-negative bacteria that were tested, there were distinct differences in hydrogen peroxide production. This proves that the innate immune system has the ability to respond dynamically and rapidly, after infection prior to the activation of the adaptive immune system.

Costs and benefits of cervical screening. I. The costs of the cervical screening programme.

In 1991, the average total Health Service cost of a cervical smear, including follow up at the colposcopy clinic, was almost 22.70 pounds in the Perth and Kinross district of Scotland. The average cost per colposcopy clinic visit was 30 pounds. The main cost elements were in general practice (55% of total) and the laboratory (33%), and most of the cost was for staff time.

Costs and benefits of cervical screening. III. Cost/benefit analysis of a call of previously unscreened women.

A population-based cervical screening programme issued invitations to women with no record of a previous smear. This call was very good value, at 5780 Pounds per life saved or 159 Pounds per life-year saved at 1991 prices. The first priority for the cervical screening service should be comprehensive coverage.

Cervical screening in Perth and Kinross since introduction of the new contract.

OBJECTIVE: To determine changes in the cervical screening service since the introduction of the new general practitioner contract on 1 April 1990. DESIGN: Analysis of computerised records of cervical screening both before and after introduction of the new contract. SETTING: General practices in Perth and Kinross Unit, Tayside. PATIENTS: A total of 30,071 women aged 21-60 on 26 general practitioner partnership lists. MAIN OUTCOME MEASURES: Percentage average of target population for cervical screening in each practice for first three quarters on introduction of the contract. RESULTS: Perth and Kinross Unit completed a computerised cervical screening call programme in July 1989, which produced an increase from 71% to 78% in the mean percentage of women aged 20-60 who had had cervical smear tests within 5.5 years. Six months after the introduction of the new general practitioner contract the mean population coverage was increased to 85% in women aged 21-60 and only four practices had not attained the 80% upper target compared with 10 on 1 April 1990. Detailed examination of randomly selected practices immediately before the new contract was introduced showed an average artificial list inflation of 4.3% in health board records when compared with practice records, a hysterectomy rate of 6.2%, and an additional 3% of women who were considered to be ineligible for smear testing due to putative virginity or illness or infirmity, or both. There was a considerable shift away from use of well woman clinics (2.7% of smears in 1990 compared with 5.6% in 1988) for taking cervical smears, potentially threatening the long term viability of the clinics. CONCLUSION: The introduction of the new contract for general practitioners has brought about a further sustained increase in population coverage for cervical screening in a small Scottish unit with a stable population, well motivated general practitioners, and a fully integrated computerised call and recall system based on the community health index. To optimise the screening service revision of the targets levels is necessary.

How complete can cervical screening be? The outcome of a call screening programme for women aged 20-60 years in Perth and Kinross.

In this paper a computer system for cervical screening call and recall based on the Community Health Index (CHI) population data-base is described. It allows the unscreened population to be identified and located on an individual general practice basis. The results of the call programme on 9517 women aged 20-60 years listed on the CHI and with no record of a cervical smear is described. There was a 24% smear uptake in the call programme which meant that after the call programme the total population cover had risen from 71% to 78%. In addition, if women with a valid reason are excluded, and the data-base corrected for women no longer in the area, the true cover rises to 88%. An analysis of the percentage cover in each GP practice is described with the implications for implementation of screening targets for primary care.

Evaluation of a call programme for cervical cytology screening in women aged 50-60.

For many years Tayside has benefited from a successful opportunistic cytology screening programme. In recent years, however, the decrease in mortality due to cervical cancer has levelled off, with most cases of severe disease arising in women who have not been screened. In view of this the health board developed a new computer system for call and recall based on the community health index. This facility allowed the unscreened population to be identified and located on an individual general practice basis. The findings of the call programme in the 3136 women aged 50-60 were studied. The 29 practices in Perth and Kinross participated in the scheme. Before the call started 4287 out of 7423 (58%) women had been screened, and after the call programme this had risen to 5109 (69%). Moreover, a further 1158 (15%) women were identified who had a valid reason for exclusion from the programme. This meant that 6267 (84%) women of the study population were accounted for by the system. The call programme in Tayside will be completed in 1989 and will include all women aged 20-60.