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.     

Dual suppression with oral contraceptives and gonadotrophin releasing- hormone agonists improves in-vitro fertilization outcome in high responder patients

Certain patients have a tendency for high response to gonadotrophin therapy which is often not ameliorated with prior gonadotrophin- releasing hormone agonist (GnRHa) suppression. As a result, these patients are frequently cancelled and often experience ovarian hyperstimulation syndrome (OHSS) episodes during in-vitro fertilization (IVF)-embryo transfer cycles. Patients with polycystic ovarian syndrome (PCOS) have been noted to be particularly sensitive to exogenous gonadotrophin therapy. We have developed a protocol which is effective in improving IVF outcome in high responder patients, including those with PCOS. Oral contraceptive pills (OCP) are taken for 25 days followed by s.c. leuprolide acetate, 1 mg/day, which is overlapped with the final 5 days of oral contraceptive administration. Low-dose gonadotrophin stimulation is then initiated on the third day of withdrawal bleeding in the form of either human menopausal gonadotrophins or purified urinary follicle-stimulating hormone at a dosage of 150 IU/day. Over a 5 year period, we reviewed our experience utilizing this dual method of suppression in 99 cycles obtained in 73 high responder patients. There were only 13 cancellations prior to embryo transfer (13.1%). The clinical and ongoing pregnancy rates per initiated cycle were 46.5 and 40.4% respectively. Only eight patients experienced mild-moderate OHSS following treatment. For those patients who had undergone previous IVF-embryo transfer cycles at our centre, significant improvements were noted in oocyte fertilization rates, embryo implantation rates and clinical/ongoing pregnancy rates with this protocol. Hormonal analyses revealed that the chief mechanism may be through an improved luteinizing hormone/follicle-stimulating hormone ratio following dual suppression. An additional feature of this dual method of suppression is significantly lower serum androgen concentrations, particularly dehydroepiandrosterone sulphate.      

Coronary risk factors in school children in relation to their family history of coronary heart disease and hyperlipidemia

A school-based study was implemented to assess the family history of coronary heart disease (CHD) and hyperlipidemia (HL) in relation to serum lipoprotein and apolipoprotein levels. One hundred and twenty-five elementary school students (aged9–10 years) and 297 junior high school students (aged12–13 years) participated. Family history was evaluated by the following scoring method: positive family history in a parent. 2 points: in a grandparent. 1 point: and onset of CHD before age 60, 1 additional point. Family history of HL was positive in 8.2% of elementary school students, and 4.2% in junior high school students. Family history of CHD was positive in 11.5% of elementary students, and 11.0% in junior students. Family history score (FHS) for HL was related to serum total cholesterol (TC), low density lipoprotein cholesterol (LDLC), high density lipoprotein cholesterol, apolipoprotein A-T, apolipoprotein B (apoB) and lipoprotein (a) in elementary students, and to TC, LDLC, triglyceride and apoB in junior students. There was no relationship between FHS for CHD and serum lipoprotein or apolipoprotein levels in any student. The children with a positive FH of HL already demonstrated an atherogenic lipid profile while those with FH of CHD did not. which was probably because lipid profiles in children are more genetically mediated by a FH of HL than of CHD.     

Cellular and sub-cellular localisation of GABA(B1) and GABA(B2) receptor proteins in the rat cerebellum

Following the recent discovery that GABA(B) receptors expressed in cell lines are only functional when both GABA(B1) and GABA(B2) are expressed, the present study reports on the development of polyclonal antisera specific for carboxyl-terminal portions of the two related GABA(B) receptor components respectively. Western blotting indicated the specificity of affinity-purified antibodies for native or recombinant expressed GABA(BR1) and GABA(BR2), with no cross-reactivity, both antisera detecting the heterodimer in rat cerebellar membranes. Immunohistochemistry revealed a distinct distribution of both receptor proteins in rat cerebellum. GABA(B1) immunoreactivity was primarily located in the granule cell layer and Purkinje cells, with discrete immuno-positive cell bodies being present in the molecular layer. GABA(B2) staining revealed intense immunoreactivity in the molecular layer, with weaker staining in the granule cell layer. Purkinje cell bodies were less intensely immuno-positive for GABA(B2). Co-localisation of both receptor proteins was observed using double immunofluorescence techniques, consistent with the notion that both proteins are required for the formation of functional GABA(B) receptors in vivo. Immunofluorescence also indicated that GABA(B) receptors did not co-localise with glial fibrillary acid protein, confirming a neuronal localisation for GABA(B) receptors. Electron microscopic analysis of the molecular layer revealed that the distribution of immunolabelling for both GABA(B1) and GABA(B2) was mainly located on the membrane of Purkinje cell dendrites and spines and in parallel fibre terminals.     

Trends in bacterial pathogens of lower respiratory tract infections

OBJECTIVES: This study was conducted to determine the bacterial aetiology of lower respiratory tract infections in this environment as well as update the clinicians in the various antimicrobial alternatives available in the treatment. METHODS: Between September 2002 and February 2005, 157 bacterial pathogens from 556 patients with lower respiratory tract infections were isolated from sputum specimens, and subjected to susceptibility testing, using standard bacteriologic techniques. RESULTS: Out of the 556 cases, only 150 (27%) had an established bacterial aetiology. One pathogen was demonstrated in 143 (95.3%) patients and seven (4.7%) had mixed infections. The most prevalent single pathogen was Klebsiella pneumoniae (38%) while the most prevalent bacterial combination was Klebsiella and Pseudomonas species (2%). Isolates of Klebsiella pneumoniae were susceptible to ciprofloxacin, gentamicin and ceftriaxone. CONCLUSIONS: Bacteriological diagnosis and antibiotic resistance surveillance are indispensable in the effective management of lower respiratory tract infections.     

An evaluation of the role of noninvasive positive pressure ventilation in the management of acute respiratory failure in a developing country

OBJECTIVE: Noninvasive positive pressure ventilation (NIPPV) has been shown to decrease the need for invasive mechanical ventilation (MV) in patients presenting with acute respiratory failure (ARF). We conducted a prospective study to assess if NIPPV use, in a developing country, was associated with clinical and physiological improvements. DESIGN: Prospective observational study. MATERIALS AND METHODS: Forty patients admitted to a medical intensive care unit during a 2-year period who fulfilled criteria for inclusion formed the study cohort to receive NIPPV. FINDINGS: Baseline (mean +/- SD) pH, PaCO 2 and PaO 2 were 7.25 +/- 0.08, 76.6 +/- 20.9 and 79.18 +/- 40.56 mmHg respectively. The primary indication for NIPPV was hypercapnic respiratory failure (n = 36, 90%). The success rate with NIPPV was 85%, with 34 of 40 patients weaned successfully. Significant improvements were observed at 1 hour following institution of NIPPV in pH (7.31 +/- 0.09, P 2 (65 +/- 17.9, P 2 54.7 +/- 20) and maintained (within 12 h) postweaning from the ventilator (pH 7.39 +/- 0.08, PaCO 2 51.9 +/- 12.4). No significant change in the PaO 2 was observed during NIPPV; PaO 2 after 1 h, prior to weaning and after weaning was 90.53 +/- 42.85, 84.80 +/- 33.76, 78.71 +/- 43.81 respectively. CONCLUSION: This study has demonstrated benefits of NIPPV in avoiding the need for invasive MV in patients presenting with ARF of diverse etiology, with results comparable to developed nations. Increased use of NIPPV in ARF is likely to impact favorably in nations with limited resources.     

Barium chloride dose‐dependently induced heart and lung injury in Wistar rats

Barium (Ba) is one of the environmental pollutant metals that incite deleterious effects on human health. The present study investigated the effects of exposure to different doses of barium chloride (BaCl₂) on heart and lung of Wistar rats. Rats were exposed to BaCl₂ at 150, 300, and 600 mg/L for seven consecutive days. Results indicated that exposure to Ba caused heart and lung damage evidenced by significant increase in plasma lactate dehydrogenase and creatine kinase activities, total cholesterol, triglyceride, and low‐density lipoprotein‐cholesterol levels, while high‐density lipoprotein‐cholesterol level decreased when compared with control. Moreover, BaCl₂ significantly decreased superoxide dismutase, catalase, and acetylcholinesterase activities as well as glutathione level in heart and lung of the treated rats. Furthermore, the dose‐dependent increase in cardiac and lung lipid peroxidation, advanced oxidative protein product and nitric oxide levels were accompanied by marked increase in metallothionein in the BaCl₂‐treated rats. Administration of BaCl₂ altered hematological parameters and significantly increased concentrations of interleukin‐6 in the treated rats. Histology analysis showed significant alteration in the heart and lung tissues of Ba‐treated rats. In conclusion, BaCl₂‐induced heart and lung damages via disruption of antioxidant defense systems, and activation of inflammatory mediators and alteration in hematological parameters in rats.     

Southwick's head-shaft angles: normal standards and abnormal values observed in obesity and in patients with epiphysiolysis

Southwick's angles measured in the anteroposterior and Lauenstein frog-leg views have been used for planning surgical treatment of deformities caused by slipped capital femoral epiphysis (SCFE). Clinically established epiphysiolysis is associated with a decrease in anteroposterior angles and an increase in Lauenstein angles. Obesity is one of the factors involved in the development of SCFE, but its influence in Southwick's angles has not been previously described. Additionally, few reports describe normal values adjusted for sex and bone age. In this study, we determined Southwick's angles in normal control participants (n=70), in patients with obesity (n=31) and in patients with epiphysiolysis (n=33). The intra-observer variations were 1.7 and 23.3% for the anteroposterior and Lauenstein angles, respectively. No significant differences were detected in the control group when these individuals were compared according to sex or chronological age. Obese patients showed a significant increase in the anterposterior angle when compared with control individuals. The hip with epiphysiolysis presented a significant reduction in the anteroposterior angle and an increase in the Lauenstein angle, when the same was compared with the contralateral hip or with the control values. In patients with unilateral SCFE the Lauenstein angle of the normal hip was detected as increased, which was possibly related to the obesity associated with decreased insulin resistance presented by these patients. We conclude that the detection of risk for developing SCFE should include an expanded clinical and radiological profile characterized by pubertal males who present obesity associated with insulin resistance and an increase in Southwick's anteroposterior angle.     

Biological evaluation of glass ionomer cements

Summary. Sixty human premolar and canine teeth were used in this study. Class V cavities were prepared with a turbine handpiece. The experimental material was ASPA, with silicate cement and zinc oxide-eugenol cements being used as controls. The teeth were extracted approximately 4 days, 30 days or 90 days after insertion of the filling material. They were demineralized and prepared for histological examination. The test procedure and evaluation closely followed recommendations by the FDI (1980). The reaction at the short time interval for each material was similar, while at the intermediate and long periods silicate cement caused the most inflammation, zinc oxideeugenol cement the least, and ASPA an intermediate response. The reaction to ASPA was reduced at the long period compared with the intermediate period.