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Biomedical subjects

P D O Davies

Publications and source records attributed to P D O Davies.

15 recordsLinked to original sources
PubMed2006

Pleural tuberculosis.

Pleural effusions in tuberculosis are commonly seen in young adults as an immunological phenomenon occurring soon after primary infection. However, the epidemiology and demographics of tuberculous pleurisy are changing due to the impact of HIV co-infection and the increasing number of pleural effusions seen as part of re-activation disease. Pleural biopsy for histology and culture is the mainstay of diagnosis with closed needle biopsy adequate in the majority of cases. Techniques such as PCR of biopsy specimens and the role of pleural fluid ADA are still being evaluated as a diagnostic aid. Tuberculous empyema is less commonly seen in the western world and the diagnostic yield from pleural fluid here is greater than in "primary" effusions. Treatment with appropriate antituberculous chemotherapy is generally successful though there is currently insufficient evidence to recommend the routine use of corticosteroids in this condition.

AIDS-Related Opportunistic Infections↗
PubMed2005

Smoking and tuberculosis: the epidemiological association and immunopathogenesis.

There is increasing evidence of a link between tuberculosis and smoking. This paper reviews the epidemiological evidence from the UK, China, India and the USA, summarizing some of the main papers which indicate an association. Where an association has been found there seems to be an increase in tuberculosis case rates of between two- and four-fold for those smoking in excess of 20 cigarettes a day, but it may be difficult to control for other factors, particularly alcohol consumption. The final part of the paper reviews possible mechanisms. A likely possibility is that nicotine turns off the production of TNF-alpha by the macrophages in the lungs, rendering the patient more susceptible to the development of progressive disease from latent Mycobacterium tuberculosis infection.

Adolescent↗
PubMed2005

Microbiological validation of smear microscopy after sputum digestion with bleach; a step closer to a one-stop diagnosis of pulmonary tuberculosis.

BACKGROUND: Smear microscopy is relatively insensitive for the diagnosis of TB. The digestion of sputum with household bleach prior to smear preparation has been reported to improve its sensitivity. This method has not been validated. METHODS: Seven hundred and fifty six patients with symptoms suggestive of pulmonary TB (PTB) were asked to submit 3 sputum specimens for direct microscopy. One specimen was selected at random for culture and another specimen was digested to prepare a further smear. The WHO case definition (>or=2 positive smears or one positive smear and positive culture) was used to compare the sensitivity and specificity of the smears. FINDINGS: Four hundred and fifty five (60%) patients were culture-positive. Of these, 235 (31%) had "definite" PTB and 223 (29%) "very likely" PTB (smear-negative, culture-positive). The WHO case definition identified 51% (235/458) of the patients with "definite" or "very likely" PTB. One digested smear detected 219 (93%) of the 235 patients with "definite" PTB and 10 patients with "very likely" PTB (sensitivity (95%CI) 50% (45-55%); specificity 99% (97-100%)). The positive and negative predictive values for one digested smear were 98% (95-99%) and 56% (52-60%) respectively, which were not different (p>0.5) to the WHO case definition (100% and 57%, respectively). INTERPRETATION: One bleach-digested smear is as sensitive and specific as the WHO case definition for the diagnosis of PTB.

Bacteriological Techniques↗
PubMed2005

Risk factors for tuberculosis.

The risk of developing tuberculosis is dependent on both the risk of being infected and the risk of infection leading on to active disease. The former will depend on the incidence of tuberculosis in the community where the individual lives or works. The latter will depend on many factors impinging on the individual both genetic and environmental. The greatest single risk factor for developing tuberculosis from infection is concurrent HIV infection. Where these two infections are prevalent tuberculosis case rates have risen dramatically and will continue to do so unless either infection can be curtailed.

AIDS-Related Opportunistic Infections↗
PubMed2004

War and peace.

Explore the source record for details and available documents.

Disease Outbreaks↗
PubMed2004

Decreasing tuberculosis case fatality in England and Wales, 1988-2001.

SETTING: Despite declining tuberculosis mortality per head of population, there was little change in tuberculosis case fatality in England and Wales from 1974 to 1987. OBJECTIVE: To determine the trend in tuberculosis case fatality for England and Wales from 1988 to 2001. DESIGN: Annual deaths to notifications ratios (DNRs) for tuberculosis were calculated using published notification and mortality data, and analysed by age group and three disease sites (central nervous system [CNS], respiratory and other). DNRs for seven disease sites (miliary, bone and joint, CNS, respiratory, genitourinary, gastrointestinal and other) were calculated for 1998 and 1999 combined, using additional data from the enhanced tuberculosis surveillance programme. RESULTS: DNR for all ages and disease sites combined fell from 9.26% in 1988 to 5.59% in 2001 (r = -0.90; 95%CI -0.97 - -0.70). DNRs for 1998-1999 combined were 41% for miliary disease, 17% for bone and joint disease, 8% for CNS disease, 7% for respiratory disease, 2% for genitourinary and gastrointestinal disease and 0.6% for other disease. CONCLUSIONS: Some of the decrease in DNRs may be due to improving notification rates. True declines in overall case fatality reflect increases in the proportion of tuberculosis patients in younger age groups and with low mortality extra-pulmonary disease.

Adolescent↗
PubMed2002

A world-wide internet survey of public knowledge about tuberculosis.

Four simple multiple-choice questions about tuberculosis (TB) were posted on a non-medical internet site for a 2-month period. A total of 564 responses were received. Sixty-two were excluded as individuals had made multiple attempts at the questions. Sixty-five per cent of responses were from North America, 14.5% from Europe and 12% from Australia and New Zealand, with only a small number of responses from Africa, the Indian subcontinent and South America. Of the respondents 49.5% correctly answered that cough is the commonest symptom of TB, 45% knew that TB was transmitted mainly by air-borne droplets, 37.8% knew that TB was caused by a bacterium. Only 19.5% knew that the most important risk factor for developing TB was HIV infection and only 4% answered all questions correctly. This survey suggests that knowledge about tuberculosis is limited in computer-literate individuals throughout the world.

Adult↗