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Biomedical subjects

P Prior

Publications and source records attributed to P Prior.

At least 19 recordsLinked to original sources
PubMed2001

Natural history of cervical human papillomavirus infection in young women: a longitudinal cohort study.

BACKGROUND: Laboratory and epidemiological research suggests an association between human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN). We studied the natural history of incident cervical HPV infection and its relation to the development of CIN. METHODS: We recruited 2011 women aged 15-19 years who had recently become sexually active. We took a cervical smear every 6 months and stored samples for virological analysis. We immediately referred all women with any cytological abnormality for colposcopic assessment, but postponed treatment until there was histological evidence of progression to high-grade CIN. FINDINGS: In 1075 women who were cytologically normal and HPV negative at recruitment, the cumulative risk at 3 years of any HPV infection was 44% (95% CI 40-48): HPV 16 was the most common type. The cumulative risk at 3 years of detecting an HPV type not present in the first positive sample was 26% (20-32). 246 women had an abnormal smear during follow-up, of whom 28 progressed to high-grade CIN. The risk of high-grade CIN was greatest in women who tested positive for HPV 16 (risk ratio 8.5 [3.7-19.2]); this risk was maximum 6-12 months after first detection of HPV 16. All HPV types under consideration were associated with cytologically abnormal smears. Although abnormality was significantly less likely to be associated with low-viral-load samples, the cumulative risk at 3 years of a high-viral-load sample after a low-viral-load sample was 45% (95% CI 35-56). Five women who progressed to high-grade CIN consistently tested negative for HPV. INTERPRETATION: Our findings suggest that attempts to exploit the association between cervical neoplasia and HPV infection to improve effectiveness of cervical screening programmes might be undermined by the limited inferences that can be drawn from the characterisation of a woman's HPV status at a single point in time, and the short lead time gained by its detection.

Adolescent↗
PubMed2000

Partial sequencing of the hrpB and endoglucanase genes confirms and expands the known diversity within the Ralstonia solanacearum species complex.

We determined partial hrpB and endoglucanase genes sequences for 30 strains of Ralstonia solanacearum and one strain of the blood disease bacterium (BDB), a close relative of Ralstonia solanacearum. Sequence comparisons showed high levels of variability within these two regions of the genome involved in pathogenicity. Phylogenetic analysis based upon sequence comparisons of these two regions revealed three major clusters comprising all Ralstonia solanacearum isolates, the BDB strain constituted a phylogenetically distinct entity. Cluster 1 and cluster 2 corresponded to the previously defined divisions 1 and 2 of Ralstonia solanacearum. Moreover, two subclusters could be identified within cluster 2. The last cluster, designated cluster 3 in this study, included biovar 1 and N2 strains originating from Africa. This recently described group of strains was confirmed to be clearly different from the other strains suggesting a separate evolution from those of both divisions 1 and 2.

Africa↗
PubMed2000

Nine year follow-up study of morbidity and mortality in retinal vein occlusion.

PURPOSE: The aim of this study was to conduct a detailed retrospective follow-up of a large cohort of patients with retinal vein occlusion (RVO), examining morbidity and mortality, to investigate a possible relationship between RVO, large vessel disease and stroke, and to determine whether recurrence of RVO was influenced by treatment of associated medical conditions. METHODS: A follow-up study was undertaken in 1994 of all patients (n = 588) who presented to the medical ophthalmology clinics of the Birmingham and Midland Eye Hospital between 1982 and 1989 with a definitive diagnosis of RVO. RESULTS: Follow-up data were obtained on 549 patients (93%). Results showed that recurrence of RVO in the same or fellow eye was decreased by more than half in the follow-up group (3.3%) when compared with the known recurrence rate at initial presentation (8.8%). Comparison of the deceased with the survivors showed that the deceased patients were significantly older (mean age 70.2 vs 63.4 years). The prevalence of rubeosis iridis and smoking were statistically significantly increased when comparing the deceased with the survivors (p < 0.016 and p < 0.008 respectively). The deceased had a higher prevalence of diabetes (15.8% vs 10.1%), and there was a trend towards increased clinically evident macrovascular disease in those patients who had died (23.2% vs 19.5%). Neither hypertension nor hyperlipidaemia predicted death, as the prevalence rates of the two conditions were similar in survivors and those who had died (60.0% vs 60.6% and 48.4% vs 53.3%). The percentage of patients taking antiplatelet drug therapy was not different in the two groups (36.8% vs 38.3%). Analysis of the causes of death of the RVO population (n = 95) compared with the causes of death in the West Midlands population as a whole, showed that the percentage of deaths from myocardial infarction in the RVO population was significantly higher (23.1% vs 14.4%, p < 0.05). There was no statistical difference between the populations for ischaemic heart disease and stroke, although there was a trend for increased mortality from stroke (19% vs 13.5%). CONCLUSION: These data suggest a relationship between RVO, mortality and increased cardiovascular risk factors (smoking, diabetes and macrovascular disease), and support the possibility of an association between RVO and stroke. They also support the potential value of medical treatment of underlying medical conditions in preventing recurrence of RVO.

Adult↗
PubMed2000

Acidovorax anthurii sp. nov., a new phytopathogenic bacterium which causes bacterial leaf-spot of anthurium.

The bacterial leaf-spot of anthurium emerged during the 1980s, in the French West Indies and Trinidad. This new bacterial disease is presently wide spread and constitutes a serious limiting factor for commercial anthurium production. Twenty-nine strains isolated from leaf-spots of naturally infected anthurium were characterized and compared with reference strains belonging to the Comamonadaceae family, the genera Ralstonia and Burkholderia, and representative fluorescent pseudomonads. From artificial inoculations 25 out of 29 strains were pathogenic on anthurium. Biochemical and physiological tests, fatty acid analysis, DNA-DNA hybridization, 16S rRNA gene sequence analysis, DNA-16S RNA hybridization were performed. The 25 pathogenic strains on anthurium were clustered in one phenon closely related to phytopathogenic strains of the genus Acidovorax. Anthurium strains were 79-99% (deltaTm range 0.2-1.6) related to the strain CFBP 3232 and constituted a discrete DNA homology group indicating that they belong to the same species. DNA-rRNA hybridization, 16S rRNA sequence and fatty acid analysis confirmed that this new species belongs to the beta-subclass of Proteobacteria and to rRNA superfamily III, to the family of Comamonadaceae and to the genus Acidovorax. The name Acidovorax anthurii is proposed for this new phytopathogenic bacterium. The type strain has been deposited in the Collection Française des Bactéries Phytopathogènes as CFBP 3232T.

Base Composition↗
PubMed1998

[Quantitative EEG in assessment of anesthesia depth. Methods of comparison].

Methodology for assessment of depth of anaesthesia based on analysis of the electroencephalogram (eeg) is controversial. Techniques range from display of single measures, for example median value of the frequency spectrum, to dedicated pattern recognition systems based on measures of several eeg features. We have compared the performance of four techniques using tape-recorded data from 23 patients anaesthetised with either halothane or isoflurane using standardised regimens. The techniques were: median frequency, spectral edge frequency, the cerebral function analysing monitor (CFAM-1) and a depth of anaesthesia monitor based on eeg pattern recognition (ADAM). Dose-response curves are presented for stepwise increases in stable end-tidal concentrations of each agent. Results indicated considerable inter-patient variability and showed the limitations of single eeg measures, particularly with deeper anaesthesia producing burst suppression patterns in the eeg. Pattern recognition techniques reduced these difficulties and appeared to be promising over a wide range of anaesthetic levels.

Anesthesia↗
PubMed1998

International differences in survival from colon cancer: more effective care versus less complete cancer registration.

BACKGROUND: Reporting of a recent international comparison of cancer survival rates has left an impression of inadequate treatment of patients in the UK but failed to address adequately the extent to which differences in survival may reflect variation in the completeness and accuracy of cancer registration. The aim of this study was to quantify the extent to which differences in registration practice may confound comparisons of survival from cancer of the colon. METHODS: A cohort of incident cases of colon cancer identified from records held by the North Western Regional Cancer Registry was used to simulate the effects on survival of changes in clinical and registration factors. The survival curve produced after each simulation was compared with that for aggregated data from 21 European registries. RESULTS: The observed survival differences were not explained by more effective primary treatment or by misclassification of in situ cases as malignant disease, whereas the exclusion of cases with only a clinical diagnosis produced estimates close to those of the European cohort. CONCLUSION: The observed survival differentials may not be due to differences in the quality of care but may reflect the failure of some European registries to register all patients with advanced disease.

Cohort Studies↗
PubMed1998

Longterm mortality outcome in patients with rheumatoid arthritis: early presenters continue to do well.

OBJECTIVE: Patients with rheumatoid arthritis (RA) have reduced life expectancy; however, there are few data on the changing pattern of causes of death with longterm followup, or on the longterm effect of early presentation. The objectives of this study were (1) to examine the effect of early presentation on subsequent mortality; (2) to compare the causes of death early and late in the followup period; and (3) to compare survival of the cohort with that of the general population (adjusted for age and sex) over a followup period of up to 27 years. METHODS: A cohort of 448 patients with RA (inpatients and outpatients), assembled 1968-74, were followed to December 31, 1990. Death certificates were obtained for all who had died and coded using the International Classification of Diseases. Kaplan-Meier survival curves were constructed. RESULTS: By the end of the study, 266 patients (59%) had died. The standardized mortality ratio (SMR) was 2.7 (95% CI 2.4-3.1). Patients who presented early continued to do well. Most excess deaths were due to cardiovascular disease. SMR due to infection, renal failure, and non-Hodgkin's lymphoma rose with disease duration. CONCLUSION: Patients with RA should be referred early, and those with chronic disease should be closely monitored for evidence of infection and renal impairment.

Adult↗
PubMed1997

Childhood cancer and parental use of tobacco: deaths from 1971 to 1976.

Parental smoking data have been reabstracted from the interview records of the Oxford Survey of Childhood Cancers (deaths from 1971 to 1976). Reported smoking habits for the parents of 2587 children who died with cancer were compared with similar information for the parents of 2587 healthy controls (matched pairs analysis). Maternal daily consumption of cigarettes and paternal use of pipes or cigars were unimportant, but there was a statistically significant positive trend between paternal daily consumption of cigarettes and the risk of childhood cancer (P < 0.001). This association could not be explained by maternal smoking, social class, parental ages at the birth of the survey child, sibship position or obstetric radiography. Relations between maternal consumption of cigarettes and birth weights suggested that (maternal) smoking data were equally reliable for case and control subjects. About 14% of all childhood cancers in this series could be attributable to paternal smoking. These data were combined with smoking data from two previously published reports from the Oxford Survey (deaths from 1953 to 1955, deaths from 1977 to 1981) to obtain further information on risks for different types of cancer and different ages at onset of disease. Paternal cigarette smoking emerged as a potential risk factor both for the generality of childhood cancer and for all ages at onset.

Adolescent↗
PubMed1997

Sex hormone preparations and retinal vein occlusion.

Retinal vein occlusion (RVO) is most commonly seen in middle-aged or older patients and is associated with underlying cardiovascular risk factors. It is much less common in younger patients. Use of the oral contraceptive pill (OCP) is known to be a risk factor for cardiovascular and cerebrovascular disease. There have previously been a few isolated case reports of patients sustaining an RVO whilst taking the OCP. The aim of this study was to investigate patients sustaining an RVO whilst taking the OCP or hormone replacement therapy (HRT). From a large series of 588 patients, we found 11 with an RVO associated with sex hormone preparations. Of these, 6 had taken the OCP and 5 were HRT users. From this large group there were only 9 female patients aged under 35 years who sustained an RVO. Of these, 6 were associated with use of the OCP. All patients were investigated for recognised medical risk factors for RVO. None of these factors were identified in the patients who had used the OCP. Of the patients taking HRT, 4 of the 5 had other potential risk factors. From our large series, the prevalence of RVO in female patients under 35 years taking the OCP was 66%. There is a 30% uptake of the OCP in the general population. These data support the view that RVO is a contraindication to the use of the OCP. Additionally, it would appear (albeit from limited data) that patients who sustain RVO may continue with their HRT, as HRT is not a major single risk factor for RVO.

Adult↗
PubMed1996

The rationale and utility of neurophysiological investigations in clinical monitoring for brain and spinal cord ischaemia during surgery and intensive care.

This review concerns the role of neurophysiological monitoring in prevention of damage to the brain or spinal cord from inadequate supply of oxygenated blood during surgery and intensive care. The spontaneous and evoked electrical activity from neurones depends on oxidative metabolism of glucose, the substrate being delivered via the arterial blood supply and not stored locally. In critical situations electrical activity declines as oxygen delivery fails. Since this happens before neuronal death occurs it can provide early warning of risk. Methods for signal processing of EEG for this purpose must include time domain assessment and recognition of burst suppression pattern, as well as frequency domain information, and provide multivariate pattern recognition. Models for monitoring systems require analysis of data sets based on clinical studies where accurate outcome data is available so that valid comparisons between different approaches can be made. Neurophysiological features must be considered in the context of other relevant clinical parameters in the design of effective warning systems for prevention of brain damage due to inadequate oxygen supply.

Brain Ischemia↗
PubMed1996

Causes of death associated with psychiatric illness.

BACKGROUND: A prospective cohort analysis of mortality, among entrants to a population-based psychiatric case register, was undertaken to identify specific causes of death responsible for the increased risk of mortality previously reported in this large group of unselected patients. METHODS: The analysis was based on a study population of 16,871 cases, aged 15-89 years, from Worcester and Kidderminster Health Districts, entering the case register between 1974 and 1984 and generating a total of 85,073 patient-years (PYR) of observation. The underlying cause of death was coded to the relevant revision of the International Classification of Diseases (ICD). Numbers of deaths observed in the study population were compared with the number of deaths expected on the basis of mortality rates for England and Wales. Comparisons were made for eight main causes of death, aggregated at Chapter level of the ICD, and 11 categories of psychiatric diagnoses. Two indices of mortality were used for evaluation: relative risk (RR) = observed deaths/expected deaths; and excess mortality rate (EMR) = (observed-expected deaths)/PYR. RESULTS: RRs were significantly raised for accidents, including suicides, as anticipated, and for various main causes of death. The increased risk of accidental death was found across the majority of the 11 psychiatric diagnostic groups although the EMRs were low at less than 5/1000 PYR. Deaths from respiratory disorders gave rise to the highest RRs after accidental deaths, and were responsible for substantial excess mortality among in-patients and patients with psychotic illnesses (especially dementia). The largest numbers of deaths of both sexes were due to diseases of the circulatory system, with a 40 per cent excess of observed over expected values in the whole series. The excess was due mainly to deaths of in-patients and of patients with psychotic diagnoses. No excess of deaths owing to neoplasms was found for either in-patients or out-patient groups. CONCLUSIONS: The findings that psychiatric illness is associated with an increased risk of death from "natural' causes and that the level of risk was related to the severity and to the diagnostic category of the illness have implications for patterns of care and use of resources.

Adolescent↗
PubMed1996

Reliability of underlying incidence rates for estimating the effect and efficiency of screening for breast cancer.

The process of setting screening performance targets requires an estimate of what the incidence of breast cancer would have been in the population invited for screening if there had not been a screening programme. Before the introduction of the National Health Service breast screening programme in 1988 the incidence of breast cancer was already increasing in the population targeted for screening. To establish the incidence before screening the most recent complete data from all the regional cancer registries were collated. An age-period model was constructed to predict what these incidence rates might now have been if the screening programme had not been introduced. The model predicted that if prescreening trends continued (between 1987 and 1995) underlying incidence over this period would increase by 2.3 per 10,000 in women aged 50-54, 2.6 per 10,000 in women aged 55-59, and 2.9 per 10,000 in women aged 60-64. If the prescreening trends have continued then the use of a universal rate, applied across all calendar years and age groups, would seem to be inappropriate when setting targets.

Adult↗
PubMed1995

Bladder tumours following chemotherapy and radiotherapy for ovarian cancer: a case-control study.

A collaborative group of cancer registries and hospitals carried out a case-control study of tumours of the bladder in women who had previously been treated for ovarian cancer. A total of 63 cases of bladder tumours were identified, and 188 controls were selected matching for age, year of ovarian cancer diagnosis and survival time. Full details of the treatment for ovarian cancer were sought for both cases and for controls. The risk of bladder tumours was increased for patients who had been treated by radiotherapy alone (1.9; 95% confidence interval, 0.77-4.9), by chemotherapy alone (3.2; 0.97-10), and by chemotherapy and radiotherapy (5.2; 1.6-16), when comparison was made with patients treated only by surgery. Patients treated by chemotherapy were separated into 2 groups according to whether they had received cyclophosphamide. Among those who had, there was a clear increase in risk (approximately 4-fold) regardless of whether or not they had also received radiotherapy. For those who received only other drugs, risk was increased substantially among patients who had also been treated by radiation, as compared with patients treated by surgery alone, and those who had received radiotherapy only. Both melphalan and thiotepa were implicated as potential bladder carcinogens on the basis of these results. The estimated risk of bladder tumours due to cyclophosphamide was more than twice the risk following radiation to the bladder, and it appeared substantially earlier. For both agents, the risk continued to increase more than 10 years after treatment began.

Aged↗
PubMed1995

Is the three year breast screening interval too long? Occurrence of interval cancers in NHS breast screening programme's north western region.

OBJECTIVE: To report the detection rate of interval cancers in women screened by the NHS breast screening programme. DESIGN: Detection of interval cancers by computer linkage of records held by the screening centres in the North Western Regional Health Authority with breast cancer registrations at the regional cancer registry. SETTING: North Western Regional Health Authority. SUBJECTS: 137,421 women screened between 1 March 1988 and 31 March 1992 who had a negative screening result. RESULTS: 297 invasive interval cancers were detected. The rate of detection of interval cancers expressed as a proportion of the underlying incidence was 31% in the first 12 months after screening, 52% between 12 and 24 months, and 82% between 24 and 36 months. CONCLUSION: The incidence of interval cancers in the third year after breast screening approaches that which would have been expected in the absence of screening and suggests that the three year interval between screens is too long.

Breast Neoplasms↗