Goeun Lee

The Association between Long Working Hours and Self-Rated Health

ObjectivesThis study was conducted to determine the number of hours worked per week by full-time wage workers by using the data of the Korean Labor and Income Panel Study (KLIPS), which represents the domestic urban area household, and to determine the association between weekly working hours and the level of self-rated health.MethodsWe used data from the 11th KLIPS conducted in 2008. The subjects of this study were 3,699 full-time wage workers between the ages of 25 and 64 years. The association between weekly working hours and self-rated health was analyzed considering socio-demographic characteristics, work environment, and health-related behaviors.ResultsAmong the workers, 29.7% worked less than 40 hours per week; 39.7%, more than 40 to 52 hours; 19.7%, more than 52 to 60 hours; and 10.9%, more than 60 hours per week. After controlling for socio-demographic variables, work environment-related variables, and health-related behavior variables, the odds ratio (OR) for poor self-rated health for the group working more than 40 hours and up to 52 hours was calculated to be 1.06 (95% confidence interval (CI), 0.89-1.27) when the group working less than 40 hours per week was considered the reference. The OR for the group working more than 60 hours was 1.42 (95% CI, 1.10-1.83) and that for the group working more than 52 hours and up to 60 hours was 1.07 (95% CI, 0.86-1.33). After stratification by gender and tenure, the OR of the female workers group and that of the group with a tenure of more than 1 year were found to be significantly higher than those of the other groups.ConclusionsThis study showed that workers working more than 60 hours per week have a significantly higher risk of poor self-rated health than workers working less than 40 hours per week. This effect was more obvious for the female workers group and the group with a tenure of more than 1 year. In the future, longitudinal studies may be needed to determine the association between long working hours and various health effects in Korean workers.

Ginger and Its Pungent Constituents Non-Competitively Inhibit Serotonin Currents on Visceral Afferent Neurons

Nausea and emesis are a major side effect and obstacle for chemotherapy in cancer patients. Employ of antiemetic drugs help to suppress chemotherapy-induced emesis in some patients but not all patients. Ginger, an herbal medicine, has been traditionally used to treat various kinds of diseases including gastrointestinal symptoms. Ginger is effective in alleviating nausea and emesis, particularly, for cytotoxic chemotherapy drug-induced emesis. Ginger-mediated antiemetic effect has been attributed to its pungent constituents-mediated inhibition of serotonin (5-HT) receptor activity but its cellular mechanism of action is still unclear. Emetogenic chemotherapy drugs increase 5-HT concentration and activate visceral vagal afferent nerve activity. Thus, 5-HT mediated vagal afferent activation is essential to provoke emesis during chemotherapy. In this experiment, water extract of ginger and its three major pungent constituents effect on 5-HT-evoked responses were tested on acutely dispersed visceral afferent neurons with patch-clamp methods. The ginger extract has similar effects to antiemetic drug ondansetron by blocking 5-HT-evoked responses. Pungent constituents of the ginger, [6]-shogaol, [6]-gingerol, and zingerone inhibited 5-HT responses in a dose dependent manner. The order of inhibitory potency for these compounds were [6]-shogaol>[6]-gingerol>zingerone. Unlike well-known competitive 5-HT3 receptor antagonist ondansetron, all tested ginger constituents acted as non-competitive antagonist. Our results imply that ginger and its pungent constituents exert antiemetic effects by blocking 5-HT-induced emetic signal transmission in vagal afferent neurons.

Development of remote healthcare system for measuring and promoting healthy lifestyle

To promote a healthy lifestyle, a web-based health self-checkup system was developed, by which users can monitor their healthy lifestyle through daily checkups and make changes based on the prescription provided. The system consists of five components: (a) daily checkup key physiological parameters related to the metabolic syndrome, such as body weight, body fat, blood pressure and blood glucose level, (b) lifestyle questionnaires, including smoking, drinking, sleeping, entertainment, exercise and eating, (c) data analysis and interpretation, (d) report and behavior modification prescription, and (e) web-based health diary and mentor service. The development and key elements of the system are described in detail.

Prostaglandin potentiates 5-HT responses in stomach and ileum innervating visceral afferent sensory neurons

Gastrointestinal disorder is a common symptom induced by diverse pathophysiological conditions that include food tolerance, chemotherapy, and irradiation for therapy. Prostaglandin E2 (PGE2) level increase was often reported during gastrointestinal disorder and prostaglandin synthetase inhibitors has been used for ameliorate the symptoms. Exogenous administration of PGE2 induces gastrointestinal disorder, however, the mechanism of action is not known. Therefore, we tested PGE2 effect on visceral afferent sensory neurons of the rat. Interestingly, PGE2 itself did not evoked any response but enhanced serotonin (5-HT)-evoked currents up to 167% of the control level. The augmented 5-HT responses were completely inhibited by a 5-HT type 3 receptor antagonist, ondansetron. The PGE2-induced potentiation were blocked by a selective E-prostanoid type 4 (EP4) receptors antagonist, L-161,982, but type 1 and 2 receptor antagonist AH6809 has no effect. A membrane permeable protein kinase A (PKA) inhibitor, KT5720 also inhibited PGE2 effects. PGE2 induced 5-HT current augmentation was observed on 15% and 21% of the stomach and ileum projecting neurons, respectively. Current results suggest a synergistic signaling in visceral afferent neurons underlying gastrointestinal disorder involving PGE2 potentiation of 5-HT currents. Our findings may open a possibility for screen a new type drugs with lower side effects than currently using steroidal prostaglandin synthetase inhibitors by selectively targeting EP4 receptor/PKA pathway without interrupt prostaglandin synthesis.

Parapheromones suppress chemotherapy side-effects

The cytotoxic drugs used in chemotherapy are often accompanied by nausea and vomiting. Despite the use of antiemetic drugs, chemotherapy-induced nausea and vomiting (CINV) remain significant side effects for cancer patients and are associated with serotonin type 3 receptor (5-HT3R) activation in the brainstem. Farnesol and nerolidol are sesquiterpene alcohols found in essential oils of plants such as roses, citronella, and lemon grass and are used as antiemetic parapheromones. Medicinal plants often are effective in treating gastrointestinal disorders, including CINV, although the mechanism of action remains unclear. In the current work, the antiemetic efficacy of the naturally occurring racemic mixture of farnesol (m-farnesol) and nerolidol (m-nerolidol) against cisplatin CINV was tested using the pica behavior (consumption of nonnutritive substances) of rats. Animals treated with m-farnesol or m-nerolidol consumed a smaller amount of kaolin than of saline-treated control animals. This result is consistent with the antiemetic efficacy of farnesol and nerolidol. Compared with controls, m-farnesol– but not m-nerolidol–treated animals consumed more food and lost less body weight. Thus, farnesol effectively reduced appetite suppression and weight loss induced by cisplatin. In separate experiments, isomers of farnesol and nerolidol were tested on 5-HT–induced responses of acutely isolated nodose neurons using patch-clamp methods. All the tested constituents inhibited 5-HT3R–mediated current in a noncompetitive manner. Thus, both farnesol and nerolidol may exert antiemetic efficacy by inhibiting 5-HT signaling in cranial visceral afferents, resulting in interruption of emetogenic signaling; however, nerolidol failed to suppress cisplatin-induced anorexia and weight loss, suggesting that additional mechanisms may contribute.