Application of an immunosensor for the detection of the β-lactam antibiotic, cephalexin

Public concern surrounding antibiotic contamination in food and food products has made it imperative to develop analytical methods for their detection. Polyclonal antibodies were used in the development of a surface plasmon resonance (SPR)-based inhibition immunoassay for cephalexin. A conjugate consisting of cephalexin-bovine serum albumin (BSA) was immobilized on the dextran gel surface of the sensor chip. Binding/regeneration studies of antibody to immobilized cephalexin were studied and dissociation of the antibody from the immobilized cephalexin was easily achieved with 10 mmol l^-1 NaOH. Forty surface regeneration cycles were carried out and found to be reproducible with only a 7.4% decrease in binding over this number of regenerations. Model inhibition immunoassays for cephalexin were developed in PBS and spiked milk samples with detection ranges of 4.88 to 2,500 ng ml^-1 and 244 to 3,906 pg ml^-1, respectively.     

Obesity: A public health problem in Ireland?

We examined the prevalence of different categories of body weight in a random sample of men and women aged 35 to 64 years studied in 1985 in County Kilkenny, Ireland. The largest group was those classified as overweight — 51.1% of men and 44.7 % of women. There were 13.7 % of men and 19.2% of women in the obese category. The obese were older but the distribution by social class did not differ significantly from the non-obese. Obese women had significantly more children born alive and a higher prevalence of positive angina questionnaire than those who were not obese. Serum total cholesterol was higher in obese men and HDL cholesterol was lower in obese men and obese women. Systolic and diastolic blood pressures were significantly higher in obese men and women but smoking status was similar. In a multiple logistic regression analysis, systolic blood pressure in men and diastolic in women remained significantly associated with obesity; there was an inverse association between obesity and HDL cholesterol in women and between obesity and HDL-cholesterol as a proportion of total cholesterol in men.     

Quality of case management of sexually transmitted diseases: comparison of the methods for assessing the performance of providers.

This article examines the reliability and validity of direct observation of patient-provider encounters, interviews with providers, and use of patients simulating sexually transmitted diseases (STD) as methods for assessing the quality of STD case management in developing countries. Data were collected during an STD health facility survey in Malawi; the performance of 49 providers was observed, and the providers were also interviewed; 20 of them were visited by a simulated patient complaining of urethral discharge. Agreement (based on the kappa statistic) was generally poor between direct observation and provider-interview data, and also between direct observation and simulated-patient data. In contrast, percentage agreements between direct observation and simulated-patient data were often high. Multiple observations on providers indicated that a provider''s behaviour is not consistent across several patients. Simulated-patient data are probably the best in reflecting normal performance, but their feasibility for routine quality assessment is limited because the provider''s behaviour is not consistent and would require multiple data points. Direct observation data are the best option for assessing quality if the results are assumed to reflect better than normal levels of quality of care. Data from interviews with providers should be viewed with caution, because they may reflect provider knowledge and not necessarily performance.     

Effects of laparotomy on systemic macrophage function.

Surgical trauma induces immunosuppression that may adversely influence survival. This study examined the effect of laparotomy on two different macrophage populations, peritoneal macrophages (PM phi) and Kupffer cells. Female, 6- to 8-week old, CFW/C3H-HeN mice (n = 160) were randomly allocated to one of three study groups: control, ether anesthetic only, or ether anesthetic and laparotomy. On postoperative days 1 and 3, PM phis and Kupffer cells were harvested and assayed for superoxide anion production (O2-), percent macrophage phagocytosis of Candida albicans (CAP), percent C. albicans killed by macrophages (CAK), percent major histocompatibility complex (MHC)-class II antigen expression, and antigen presentation. Macrophages isolated on postoperative day 1 were also cocultured with 100 units/10(6) cells/ml interferon-gamma (IFN-gamma). Laparotomy significantly impaired microbicidal activity (O2-, percent CAP, and percent CAK) and antigen presentation on postoperative day 1. On postoperative day 3, O2- and antigen presentation were increased significantly (p less than 0.05) over control values, indicating a rebound phenomenon. Kupffer cell microbicidal function was unchanged on postoperative days 1 and 3. The initial immune impairment (PM phis: O2-, CAP, and CAK) was abrogated by IFN-gamma treatment. In immunosuppressed hosts after injury, administration of macrophage-activating factors such as IFN-gamma could be of therapeutic benefit.     

Pulmonary aspergilloma. Results of surgical treatment

Between 1953 and 1984, 53 patients (40 male and 13 female) underwent thoracotomy for treatment of pulmonary aspergilloma. The median age was 58 years (range 4 to 86 years). Either underlying lung disease or immunologic risk factors were present in 49 patients (92%). Twenty-one patients (31%) had simple aspergilloma and 32 (47%) had complex aspergilloma. The most common indication for operation was an indeterminate mass, hemoptysis, or severe cough. Lobectomy, wedge excision, and pneumonectomy were the most frequent operations. Complications occurred in 78% of patients with complex aspergilloma and in 33% of patients with simple aspergilloma (p = 0.002). Operative mortality was 5% (one death) in patients with simple aspergilloma and 34% (11 deaths) in patients with complex aspergilloma (p = 0.01). Cause of death was respiratory failure in four patients, underlying pulmonary disease in three, aspergillosis in two, and other conditions in three. At follow-up, 84% of operative survivors with simple aspergilloma were alive and well compared with 43% of those with complex aspergilloma. Although operative mortality in patients with complex aspergilloma was high, 67% of the survivors had a good long-term result in terms of absence of symptoms, but they frequently died of underlying disease. In contrast, operation in patients with simple aspergilloma was done with low risk, and approximately 90% of survivors had a good late result. Late appearance of contralateral disease did occur and argues for rigorous postoperative surveillance.     

Undergraduate and postgraduate dental students''reflection on learning'': a qualitative study

The aim of this study was to explore undergraduate and postgraduate dental students' understanding of a good learning experience by using 'reflection on learning' as described by Schon. Four groups of Year 4 BDS students and one group of postgraduate students in dental public health took part in a series of focus group discussions. The responses were grouped into four broad themes (a) active, practical and positive learning; (b) interactive/together learning; (c) personal learning; (d) theory into practice. Six educational models of good learning proposed by the students are described.     

Immobilization of Aspergillus fumigatus colonies in a soft agar matrix allows visualization of A549 cell detachment and death.

A model to examine the effects of proliferating Aspergillus fumigatus ATCC 26933 colonies embedded in a thin layer of soft agar on a monolayer of A549 cells was developed and enabled an investigation of the response of cultured cells to fungal growth. This model simulates the conditions on the respiratory surface in patients with invasive aspergillosis and also in the mucus secretions of cystic fibrosis patients with allergic bronchopulmonary aspergillosis. Conidia of A. fumigatus adhering to A549 cells were immobilized in a thin layer of soft agar (0.6% (w/v)) and allowed to germinate at 37 degrees C. Fungal colonies greater than 5 mm in diameter caused rounding-up and detachment of A549 cells underneath the colony and towards the hyphal tips. As the fungal colony diameter increased, cell detachment occurred ahead of the hyphal tips. Cells detached for short periods (less than 6 h) showed no annexin-V (AV) or propidium iodide (PI) staining, suggesting no externalization of phosphatidylserine and an intact plasma membrane. Cells that had detached for periods greater than 6 h were positive for AV and PI indicating the rupture of the plasma membrane and cell death by necrosis. Chemical extraction and separation by thin layer chromatography of agar from zones of cell detachment around fungal colonies revealed the presence of three compounds that may play a role in inducing cell death.