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B Watts

Publications and source records attributed to B Watts.

12 recordsLinked to original sources
PubMed1999

Regulating plant/insect interactions using CO2 enrichment in model ecosystems.

The greenhouse environment is a challenging artificial ecosystem in which it is possible to study selected plant/insect interaction in a controlled environment. Due to a combination of "direct" and "indirect" effects of CO2 enrichment on plant photosynthesis and plant development, canopy productivity is generally increased. In this paper, we discuss the effects of daytime and nighttime CO2 enrichment protocols on gas exchange of pepper plants (Capsicum annuum L, cv Cubico) grown in controlled environments. In addition, we present the effects of thrips, a common Insect pest, on the photosynthetic and respiratory activity of these plant canopies. Carbon dioxide has diverse effects on the physiology and mortality of insects. However, our data indicate that thrips and whiteflies, at least, are not killed "directly" by CO2 levels used to enhance photosynthesis and plant growth. Together the data suggest that the insect population is affected "indirectly" by CO2 and that the primary effect of CO2 is via its effects on plant metabolism.

Animals↗
PubMed1999

Effect of hemodialysis and antiretroviral therapy on plasma viral load in HIV-1 infected hemodialysis patients.

BACKGROUND: Plasma viral load has become an important test in predicting the progress of HIV-1 infected patients. The higher the viral load the faster is the progression to AIDS. As HIV-1 infected hemodialysis (HD) patients have higher mortality and morbidity than HIV-1 infected non-dialysis patients, and as all the blood tests in the HD patients are drawn during HD, we measured the effect of HD and antiretroviral therapy on viral load in HIV-1 infected HD patients. PATIENTS AND METHODS: We measured plasma viral load pre-dialysis and post-dialysis in 10 HIV-1 infected HD patients. The viral load was measured using an in vitro quantitative nucleic acid amplification test. We also compared viral load in 8 HIV-1 infected HD patients on one antiretroviral drug with 8 HIV-1 patients on two (6) or three (2) antiretroviral drugs. RESULTS: There was a small reduction in plasma viral load postdialysis in all HIV-1 infected HD patients (45% +/- 5.4, 0.3 log +/- 0.05, p < 0.0004). However, HIV-1 RNA could not be detected in the ultrafiltrate. The patients who were on two or three antiretroviral drugs had lower viral load (8915 +/- 3702 vs. 351440 +/- 101237, p < 0.004) and higher CD4 count (355 +/- 81 vs 82 +/- 39, p < 0.009) than patients on only one antiretroviral drug. CONCLUSION: We conclude that there is a small reduction in plasma viral load in HIV-1 infected hemodialysis patients post-dialysis. As no viral RNA could be detected in the ultrafiltrate, the reduction could be due to nonspecific adsorption of the viral RNA to the dialysis membrane. HIV-1 infected hemodialysis patients who are on two or three antiretroviral drugs had significantly lower viral load and higher CD4 count than patients on only single antiretroviral drug. Therefore a single antiretroviral drug should not be used in treating HIV-1 infected HD patients.

Adult↗
PubMed1991

Case report: percutaneous drainage of periappendiceal actinomycosis.

Abdominal actinomycosis is a disorder which often complicates a chronic perforation of the gastrointestinal (GI) tract, such as at the appendix (Wyngaarden and Smith, 1988). Delayed diagnosis characterizes abdominal actinomycosis. Multiple abscesses and draining sinuses are frequently present. Treatment has consisted of long-term oral antibiotic therapy coupled with surgery, including incision and drainage of abscesses with removal of persistent sinuses (Berardi, 1979). We present a patient with abdominal actinomycosis complicating a chronically ruptured appendix who was managed by percutaneous catheter drainage and antibiotic therapy.

Abdomen↗
PubMed1981

Computed tomography in patients with psychiatric illnesses: advantage of a "rule-in" approach.

Computed tomography (CT) is used commonly to "rule-out" disease. In 123 consecutive patients with psychiatric diseases in three institutions, 105 CT scans (85.4%) interpreted as normal or normal except for atrophy did not influence management, only reassured clinicians and patients. Incidental and false positive findings were more numerous than true positive findings. All six true positive findings occurred in patients with focal findings on neurologic examination; four led to management changes. The lower 954% confidence limit of the cost of case finding by CT only was estimated to be $2931 for all patients; $603 for patients with focal findings; and at least $7083 for patients without focal findings. Computed tomography is a sensitive diagnostic method that may detect more false and incidental positive findings when used somewhat unselectively to "rule-out" disease. In these patients, a examination suggesting structural intracranial abnormalities would have been less expensive and more effective.

Adolescent↗
PubMedDate not supplied

Continuing professional development in public health medicine.

BACKGROUND: A survey of public health doctors was undertaken in the South Thames region to support coordination of continuing professional development (CPD) and to guide appropriate provision of educational activities for those working in the specialty. METHODS: A postal survey of 130 public health doctors in service, academic and military posts in the South Thames region of the UK. RESULTS: The response rate was 79% with good representation of grades and geographical areas. Public health doctors preferred personal and small group learning particularly focused on problem solving. Epidemiology as a basic discipline was rated highly by respondents, but senior doctors also showed preferences for topics beyond the textbooks. Respondents demonstrated that they had acquired such knowledge and skills, which could be shared in CPD sessions with colleagues. There was support for learning with and from non-medical colleagues. In the service posts structural change was ongoing, expectations of performance by management were high, and appropriate CPD was an expressed need, although time was seriously limited for this activity. CONCLUSIONS: Appropriate CPD could support the effectiveness of public health physicians in challenging circumstances. However, a critical evaluation of the relevance of CPD programmes to public health practice is essential if CPD is to support doctors in delivering the public health agenda in the changing structures within which they work.

Adult↗