Effects of long working hours and the night shift on severe sleepiness among workers with 12‐hour shift systems for 5 to 7 consecutive days in the automobile factories of Korea

We investigated the effects of 12‐hour shift work for five to seven consecutive days and overtime on the prevalence of severe sleepiness in the automobile industry in Korea. [Correction added after online publication 28 Nov: Opening sentence of the summary has been rephrased for better clarity.] A total of 288 randomly selected male workers from two automobile factories were selected and investigated using questionnaires and sleep‐wake diaries in South Korea. The prevalence of severe sleepiness at work [i.e. Karolinska Sleepiness Scale (KSS) score of 7 or higher] was modeled using marginal logistic regression and included theoretical risk factors related to working hours and potential confounding factors related to socio‐economic status, work demands, and health behaviors. Factors related to working hours increased the risk for severe sleepiness at the end of the shift in the following order: the night shift [odds ratio (OR): 4.7; 95% confidence interval (CI): 3.6–6.0)], daily overtime (OR: 2.2; 95% CI: 1.7–2.9), weekly overtime (OR: 1.6; 95% CI: 1.0–2.6), and night overtime (OR: 1.6; 95% CI: 0.8–3.0). Long working hours and shift work had a significant interactive effect for severe sleepiness at work. Night shift workers who worked for 12 h or more a day were exposed to a risk of severe sleepiness that was 7.5 times greater than day shift workers who worked less than 11 h. Night shifts and long working hours were the main risk factors for severe sleepiness among automobile factory workers in Korea. Night shifts and long working hours have a high degree of interactive effects resulting in severe sleepiness at work, which highlight the need for immediate measures to address these characteristics among South Korean labor force patterns.     

In vitro metabolism of the new insecticide flupyrazofos by rat liver microsomes

1. The in vitro metabolism of the new insecticide flupyrazofos was studied using rat liver microsomes. Two metabolites were produced and identified as O, O -diethyl O -(1- phenyl-3-trifluoromethyl-5-pyrazoyl) phosphoric acid ester (flupyrazofos oxon) and 1- phenyl-3-trifluoromethyl-5-hydroxypyrazole (PTMHP) based on UV and mass spectral analysis. 2. Cytochrome P450 oxidatively converted flupyrazofos to flupyrazofos oxon, a major metabolite and phenobarbital-induced microsomes increased this desulphuration by 8- fold. 3. Flupyrazofos oxon was converted to PTMHP with a half-life of 47 8?min by chemical hydrolysis and this conversion also proceeded non-enzymatically under our microsomal incubation conditions.     

Association between central venous pressure and blood loss during hepatic resection in 984 living donors

Background: Although low central venous pressure (CVP) anesthesia has been used to minimize blood loss during hepatectomy, the efficacy of this technique remains controversial. We therefore assessed the association between blood loss and CVP during hepatic resection, and examined significant determinants associated with intraoperative hemorrhage during hepatectomy in living donors.
Methods: Between April 2004 and April 2008, 984 living donors who underwent a hepatic resection were assessed retrospectively. Univariate and multivariate analyses were performed to explore the relationships between intraoperative blood loss and several variables including CVP.
Results: The mean intraoperative blood loss was 691.3 ± 365.5 ml. Only four donors required packed red blood cell transfusions (mean, 1.5 U). The mean duration of hepatic resection was 92.1 ± 26.3 min. The mean, maximum, and minimum values of CVP measured during hepatectomy were 4.6 ± 1.7, 5.3 ± 1.8, and 4.0 ± 1.8 mmHg, respectively, and were not significantly correlated with intraoperative blood loss. On multivariate analysis, predictors of hemorrhage were liver fatty change, gender, and body weight, but none of the mean CVP, surgeons, anesthesiologists, anesthesia duration, resected liver volume, hepatectomy type, systolic blood pressure, heart rate, or body temperature were significant.
Conclusions: CVP during hepatic resection was not associated with intraoperative blood loss in living liver donors, suggesting that CVP may not be an important factor in predicting blood loss during hepatectomy in healthy subjects.     

Anaesthetic requirement and stress hormone responses in patients undergoing lumbar spine surgery: anterior vs. posterior approach

Background: The intensity of nociceptive stimuli reflects the severity of tissue injury. The anaesthetic requirement and stress hormonal responses were determined to learn whether they differ according to different surgical approaches (anterior vs. posterior) during the spinal surgery.
Methods: Patients undergoing lumbar spine surgery without neurological deficits were divided into two groups: one having posterior ( n =13) and the other having anterior fusion ( n =13). The end-tidal sevoflurane concentrations (ET_SEVO) required to maintain the bispectral index score at 40–50 were determined. Mean arterial pressure (MAP), heart rate (HR), central venous pressure (CVP), serum osmolality and plasma concentrations of catecholamines, cortisol and vasopressin (AVP) were measured.
Results: There were no differences in MAP, HR, CVP and serum osmolality between the groups. ET_SEVO was higher in the anterior than in the posterior group ( P <0.05). The plasma concentrations of norepinephrine and cortisol increased in both groups during the surgery, whereas those of epinephrine remained unchanged. AVP concentrations increased during the surgery in the anterior group, and remained unaltered in the posterior group. The anterior group needed more analgesics ( P <0.01) during the first 1 h after the operation.
Conclusions: The anterior approach required a deeper level of anaesthesia while undergoing spinal surgery and more use of post-operative analgesics than the posterior approach. It was also associated with a more pronounced AVP release during the surgery.     

Expression of NEDD‐1, a PTEN regulator,in gastric and colorectal carcinomas

Recent studies have disclosed that NEDD4‐1 regulates PTEN activity by ubiquitination. NEDD4‐1 negatively regulates PTEN in cytosol and acts as an oncogenic protein. By contrast, NEDD4‐1 promotes PTEN nuclear import and acts as a tumor suppressor. Despite the importance of NEDD4‐1 in PTEN regulation in cancer cells, expression of NEDD4‐1 protein in cancer tissues is unknown. The aim of this study was to analyze NEDD4‐1 expression in colorectal and gastric cancer tissues. We investigated NEDD4‐1 protein expression in 103 colorectal and 60 gastric carcinoma tissues by immunohistochemistry using a tissue microarray approach. In the cancers, expression of NEDD4‐1 was detected in 82 (80%) of the colorectal carcinomas and 45 (75%) of the gastric carcinomas in cytoplasm. By contrast, the normal mucosal cells of both stomach and colon showed no or very weak expression of NEDD4‐1. There was no significant association of NEDD4‐1 expression with clinicopathologic characteristics, including invasion, metastasis and stage. Our data indicate that NEDD4‐1 overexpression is a feature of both colorectal and gastric carcinomas. The increased expression of NEDD4‐1 in malignant gastric and colorectal cells compared to their normal epithelial cells suggests that NEDD4‐1 expression may play a role in colorectal and gastric cancer development.     

Ultrastructural study on the follicle-associated epithelium of nasal-associated lymphoid tissue in specific pathogen-free (SPF) and conventional environment-adapted (SPF-CV) rats

Membranous (M) cells in follicle-associated epithelium (FAE) play an important role in the mucosal immunity through transport of a variety of foreign antigens to the underlying mucosa-associated lymphoid tissue (MALT). We aimed to investigate the ultrastructure of M cells in the FAE covering nasal-associated lymphoid tissue (NALT) both in specific pathogen-free (SPF) rats and in conventional environment-adapted (SPF-CV) rats aged 8–38 wk. In NALT of both SPF and SPF-CV rats, FAE included the nonciliated microvillous cell, which appears to be an analogue of M cell previously described in other MALT. In SPF rats, M cells increased in number only slightly with age, and they maintained morphological uniformity irrespective of age. In SPF-CV rats, M cells selectively increased in number resulting in prominent expansion of FAE surface area in parallel with the duration of maintenance in a conventional environment. In addition, M cells in SPF-CV rats showed heterogeneity in their surface morphology such as the length and number of microvilli and cell surface area and outline. In addition, the FAE was stratified by various subtypes of M cells, which were characterised by several subcellular alterations including the presence of many keratin filaments, homogeneous dark bodies and extensive cytoplasmic interfoliation with wide intercellular spaces filled with amorphous proteinaceous material. These characteristics of M cells in SPF-CV rat were intimately related with a preferential influx of immunocompetent cells into the FAE, which was not seen or was very rare in SPF rats irrespective of age. The results suggest the possibility that NALT may effectively carry out the mucosal immune response against antigenic stimuli of different magnitude through the unique dynamics of M cells which seem to be influenced by the infiltration of immunocompetent cells.