High-throughput fluorescence polarization immunoassay by using a portable fluorescence polarization imaging analyzer.

High-throughput fluorescence polarization immunoassays (FPIAs) for mycotoxin were conducted using a portable FP analyzer with a microdevice. Simultaneous FPIA measurements for 8 different deoxynivalenol (DON) concentrations in 12 chambers (total of 96 samples) and high-throughput FPIA measurements for single DON concentrations in more than 500 chambers were conducted. The results indicated that simultaneous FPIAs for 96 independent samples and for 500 samples were possible by FP imaging. The FP analyzer has a size of 65 cm (W 35 cm × D 15 cm × H 15 cm) and costs less than $5000. The sample volume was 1 nL. Furthermore, it is expected that sample reaction and FP detection can be automatically conducted with the analyzer by changing the microdevice and the software. Its features such as low cost and portability will contribute to on-site measurement and point-of-care testing. Additionally, the high-throughput feature will contribute to the study of molecular interactions based on FP measurements.

A compact fluorescence polarization analyzer with high-transmittance liquid crystal layer.

Fluorescence polarization (FP) offers easy operation and rapid processing, making it implementable in molecular interaction analysis. Previously we have developed a unique FP measurement system using a liquid crystal (LC) layer and an image sensor. The system is based on a principle of synchronized detection between the switching rate of the LC layer and the sampling rate of the CCD. The FP system realized simultaneous multiple sample detection; however, the measurement precision was lower than that of the conventional FP apparatus. The main drawbacks were low light transmittance of the LC layer and insufficient synchronization between the LC layer and CCD. In this paper, we developed a new FP analyzer based on LC-CCD synchronization detection. By using a newly designed LC with high transmittance and improving synchronization, the performance of the system has been dramatically improved. Additionally, we reduced the cost by using an inexpensive CCD and an LED as the excitation source. Simultaneous FP immunoassay of multiple samples of prostaglandin E2 was performed. The error rate of the FP system is reduced from 16.9% to 3.9%, as comparable to the commercial conventional FP system.

[Preventive measures against tuberculosis in working facilities and companies].

The health care program in working facilities and companies have played a significant part in prevention of tuberculosis. However, the ordinary national tuberculosis survey policy was abolished in April, 2005 and the tuberculosis survey for salary-earners is on the brink of drastic change. In this symposium the current status of the prevailing survey of tuberculosis in working facilities and companies was reviewed and the future direction of the tuberculosis survey in comparison to that in lung cancer survey was discussed. 1. Epidemiological trends of tuberculosis from the tuberculosis surveillance data: Masako OHMORI (Research Institute of Tuberculosis, Japan Anti-Tuberculosis Association). The estimated rate of tuberculosis case discovery by periodical mass screening in the working facilities was 0.033% and it was higher than that in general adult population. The detection rate of tuberculosis in nurses who suffered from tuberculosis reached 40.4% by an aid of mass X-ray screening and 8.7% by contact tracing. The risk of onset of the disease was 4.3 times higher nurses than in general at the same years of age. The importance of infection control measures in the medical facilities was emphasized. 2. Current status and problems in tuberculosis control in a large-sized company: Yusuke NAKAOKA (Department of Occupational Health, Osaka Railway Hospital, West Japan Railway Company). Some preventive modalities against TB such as periodical medical check-up and awareness programs have been done for the purpose of prevention in our company. The prevalence of the disease has significantly reduced in number. The specific circumstances in large-sized company should be taken into consideration, and it is important for company workers and health professionals to recognize their roles in preventing the infectious disease. 3. Are there any differences between clinical cases and control people working for small-sized companies in the onset of tuberculosis?: Osamu NAKASHIMA, Kohei IMOTO (Taito Health Center, Tokyo) and Toru MORI (Research Institute of Tuberculosis, JATA). We surveyed environmental conditions in working places and domestic conditions of employees who were working for small-sized companies located in Taito ward, based on written questionnaires. The companies were selected as those which had the patients of tuberculosis in the past one-year period, and the number of employees was less than ten. Compared with control people, TB patients had more frequent smoking habit (p < 0.05), and tended to have been less exposed to the sunshine at their residency and to have nutritionally poor meals and deficits of their meals. These results suggest that these factors alone or in combination may contribute to accelerated onset of tuberculosis. 4. Current status and problems in tuberculosis management among high prevalence population and in health check-up for personnel with unspecified and high occupational contact with tuberculosis patients: Hidetoshi IGARI (Division of Control and Treatment of Infectious Diseases, Chiba University Hospital), Kiminori SUZUKI (Chiba Foundation for Health Promotion and Disease Prevention). Tuberculosis prevalence is as high as 500-1500 per 100,000 peoples among the homeless and construction workers living in "Hanba", a bunkhouse. We surveyed their medical conditions through periodical or extraperiodical health check-up. We retrospectively analyzed some medical factors contributing to successful treatment of the disease. Hospital admission and enhancement of counseling opportunities were two factors leading to the success of the treatment. The ambulance attendants have a significant possibility to contact patients with TB and are high at risk of acquiring the infection. As there are often limited information on TB in patients in an emergency condition, it is difficult to protect themselves from its contagion properly. Periodical and extraperiodical health check-up is important for these personnel and application of QuantiFERON-TB 2nd generation to the personnel is new and useful for diagnosis of the latent tuberculosis infection. 5. A role of chest X-ray examination for lung cancer detection among company workers: Takeo TESHIMA (Koseikan Clinic, Miyagi Branch, Japan Anti-Tuberculosis Association). Detection rates of lung cancer in company workers and in general population under the age of 60 years were compared. Chest X-ray survey was done using 10 cm x 10 cm indirect chest X-ray films of the chest. The detection rates of lung cancer in patients with definite or suspicious diagnosis in 265,620 company workers were 2.3 and 2.6 per 100,000, respectively. On the other hand the rates were 9.9 and 8.8 per 100,000 in a general population of 811,391. Twenty-four percent of patients with suspicious diagnosis were eventually made a definite diagnosis. The corrected detection rate reached to 21.0 for male patients and 8.3 for female patients and 12.1 totally. The detection rates of lung cancer in company workers and in general population under the age of 60 years exceeded the rate of pulmonary tuberculosis. Chest X-ray examination for the detection of lung cancer and pulmonary tuberculosis is still recommended under various working and social circumstances.