Presenteeism and sleep duration on workdays and days off.

BACKGROUND: Presenteeism refers to being present at work but experiencing reduced productivity due to health problems, and has been known to be related to sleep loss. Workers commonly sleep longer on days off than on workdays, and presenteeism may be reduced with extended sleep on days off. AIMS: This study aimed to determine the association between sleep duration both on workdays and days off and presenteeism. METHODS: The participants were 1967 workers who engaged in work for 5 days and rested for 2 days weekly. Sleep duration was classified into less than 6 hours (short; S), 6-8 hours (medium; M), and 9 hours or longer (long; L), for workdays and days off, respectively. Presenteeism was assessed using the World Health Organization Health and Work Performance Questionnaire. RESULTS: On both workdays and days off, compared to medium sleep duration, short sleep duration was significantly associated with increased odds of presenteeism. The odds of presenteeism were significantly increased for S-S (odds ratio [OR] 2.17, 95% confidence interval [CI]1.40-3.37), S-M (OR 1.59, 95% CI 1.14-2.22), S-L (OR 2.71, 95% CI 1.05-7.00), and M-S (OR 6.82, 95% CI 2.71-17.17) combined sleep duration for workdays and days off, respectively, compared to an M-M (reference). CONCLUSIONS: Sleep loss on workdays cannot be compensated for with longer sleep on days off. This study suggests that sufficient sleep duration on both workdays and days off is important for reducing presenteeism.

[Usefulness of dynamic computed tomography for the diagnosis of mediastinal hemangioma].

An asymptomatic 59-year-old female was admitted with an abnormal shadow on her chest radiography. Chest computed tomography (CT) revealed a mass measuring 20 mm in the anterior mediastinum. At the arterial phase on dynamic contrast-enhanced CT (dynamic CT), the pattern of "peripheral puddles", defined as discrete well-defined peripheral enhancing globles, was found in the mass. The tumor was completely resected via a median sternotomy, and was histopathologicaly diagnosed as hemangioma. In this case, dynamic CT was very useful for the preoperative diagnosis, and then the enhancement pattern of "peripheral puddles" on dynamic CT may be a conclusive finding for the diagnosis of mediastinal hemangiomas.

Ethnic differences between Japanese and Caucasians in the expression levels of mRNAs for CYP3A4, CYP3A5 and CYP3A7: lack of co-regulation of the expression of CYP3A in Japanese livers.

Using a newly developed real-time reverse transcriptase-polymerase chain reaction method, mRNAs were quantitated for CYP3A4, CYP3A5 and CYP3A7 in adult livers from 24 Japanese and 24 Caucasian subjects to elucidate the potential ethnic differences in the expression levels of human cytochrome P450 (CYP) 3As. The expression level of CYP3A4 mRNA in Japanese livers (n = 24) was approximately three times higher than that in Caucasian livers (n = 24, p < 0.001). The mean level of CYP3A5 mRNA was approximately twice higher in Japanese (n = 9) than in Caucasians (n = 5) heterozygous for the CYP3A5 *1 allele (p = 0.057). The CYP3A7 mRNA level was twice higher in Japanese (n = 24) than in Caucasians (n = 22) carrying the CYP3A7 *1A/ *1A genotype (p = 0.042). The level of CYP3A4 mRNA did not correlate with those of CYP3A5 (r = 0.044, n = 24) or CYP3A7 (r = 0.21, n = 24) mRNAs in Japanese livers in contrast to co-regulatory expression of CYP3A4, CYP3A5 and CYP3A7 in Caucasian livers. The results indicate that there are ethnic differences in the expression levels of adult liver CYP3A mRNAs between Japanese and Caucasians, and that the mechanism(s) regulating the hepatic CYP3A expression may be different between these ethnic groups.

Cooperative regulation of CYP3A5 gene transcription by NF-Y and Sp family members.

The purpose of this study was to clarify the mechanism(s) responsible for the transcriptional regulation of the human CYP3A5 gene. It was found that a region from nucleotides -90 to -40 was involved in the transcriptional activity of the CYP3A5 gene by transfection of a series of 5'-truncated promoter-luciferase chimeric genes into human hepatoma HepG2 cells. A gel shift assay using nuclear extracts prepared from HepG2 cells showed that nuclear factor-Y (NF-Y) and specificity protein (Sp) 1 and Sp3 bound to CCAAT box (-78/-68) and a basic transcription element (BTE) (-67/-46) in the CYP3A5 gene. Furthermore, introduction of mutations in the CCAAT box, the BTE, or both elements decreased the transcriptional activity to 10, 21, or 4% of that seen with the intact gene. Thus, we conclude that the transcription of the CYP3A5 gene is cooperatively regulated by NF-Y, Sp1, and Sp3 in HepG2 cells.

Further reduction of radiation dose in helical CT for lung cancer screening using small tube current and a newly designed filter.

A new aluminum filter, 5.8 mm thick at the center, was designed. The effective energy, exposure dose, absorbed dose, and noise were measured by using low-dose technique, very low-dose technique with a conventional filter, and very low-dose technique with a new filter on a chest phantom. Accuracy of very low-dose computed tomography (CT) with a new filter was compared against standard helical CT in 40 patients and against chest radiography in 35 patients. Effective energies were 42.6 keV and 51.6 keV at a conventional filter and the new filter, respectively. Compared against 20mA with a conventional filter, exposure dose was reduced by 17%, and absorbed dose was equivalent, at 30 mA with the new filter. Noise was improved by 9%. Compared with standard helical CT, the sensitivity, specificity, and accuracy of very-low-dose helical CT were 100%, 88%, and 95%, respectively. Very-low-dose helical CT was found to be significantly superior to chest radiography in the detection of lung cancers. Using a smaller tube current and an appropriate filter allows a further reduction in radiation dose in helical CT for lung cancer screening.

Detection of subtle pulmonary disease on CR chest images: monochromatic CRT monitor vs color CRT monitor.

To clarify the diagnostic efficacy of color soft-copy computed radiographic (CR) images of the chest in the detection of subtle pulmonary abnormalities. Twenty observers compared 87 soft-copy CR images on four types of CRT monitor (nonmagnified monochromatic CRT, magnified monochromatic CRT, nonmagnified color CRT, and magnified color CRT). Of 87 test images, 45 (including two identical sets of 12 images to test intraobserver variability) were abnormal and 42 (including two identical sets of 12 images) were normal. Of the 45 abnormal images, 15 showed subtle abnormalities, 15 showed mild abnormalities, and 15 showed obvious abnormalities. In the receiver operating characteristic (ROC) analyses, there were no statistically significant differences among the four types of CRT display formats in the detection of subtle abnormalities. Color CRT monitors can replace monochromatic CRT monitors without any loss in the ability to detect subtle interstitial lung disease.

Videotaped helical CT images for lung cancer screening.

PURPOSE: The goal of this work was to determine a radiologist's ability to detect solitary pulmonary nodules on helical CT using both video (cine) viewing and film-based viewing. METHOD: Sixty-five chest helical CT studies were reviewed. Six radiologists searched for 40 lung nodules on CT images presented in three formats. Film-based viewing of images at 10 and 5 mm increments was performed with a light box. Video viewing of the same examinations was performed in 5 mm increments at 2 frames/s. The area under the receiver operating characteristic curve (Az) measured the observer's ability to detect nodules. RESULTS: The Az was 0.948 for the video viewing, 0.844 for 5 mm increment film-based viewing, and 0.879 for 10 mm increment film-based viewing. There were no statistically significant differences. CONCLUSION: Lung nodules can be detected with similar detection rates when viewing conventional film or videotaped helical CT images. Videotaped images incur a lower cost, an important consideration in mass screening for lung cancer.